UNCLOS Compulsory Conciliation: Procedure and Legal Effect
Introduction
UNCLOS compulsory conciliation allows a State Party to require another State Party to enter a settlement procedure for certain maritime disputes, even without its agreement to that particular proceeding. The United Nations Convention on the Law of the Sea (UNCLOS) establishes this mechanism through Articles 297 and 298, with Annex V governing the procedure. A conciliation commission may examine the dispute and recommend terms of settlement, but its report, including its conclusions and recommendations, is not legally binding on the parties (United Nations, 1982, Annex V, Articles 7 and 11).
The circumstances in which conciliation can be required are narrowly defined. Article 297 provides for the procedure in specified disputes concerning marine scientific research and fisheries. Article 298 permits a State Party to exclude certain maritime delimitation disputes from compulsory procedures entailing binding decisions, while requiring it to accept conciliation when the additional conditions of Article 298(1)(a)(i) are satisfied. An exclusion from compulsory adjudication does not, in these circumstances, remove every treaty-based obligation to pursue settlement (United Nations, 1982, Articles 297–298).
The distinction between participation and outcome determines the procedure’s legal effect. States may be obliged to take part in conciliation without being required to accept the commission’s proposed settlement. For qualifying maritime delimitation disputes under Article 298, however, the parties must negotiate an agreement on the basis of the commission’s report. If those negotiations fail, submission to a binding procedure under Part XV, Section 2, requires mutual consent unless the parties otherwise agree (United Nations, 1982, Article 298(1)(a)(ii)).
The Timor Sea conciliation between Timor-Leste and Australia demonstrates how these obligations can operate in practice. Timor-Leste initiated the proceedings in April 2016, and negotiations assisted by the commission led the two states to sign a maritime boundary treaty on March 6, 2018. The treaty entered into force on August 30, 2019 (Australia, Department of Foreign Affairs and Trade, n.d.). Its binding force arose from the states’ agreement, not from a settlement imposed by the commission.
1. The Legal Nature of Compulsory Conciliation
The dispute-settlement system of the United Nations Convention on the Law of the Sea (UNCLOS) does not require states parties to submit every disagreement to a court or arbitral tribunal. Part XV begins by requiring peaceful settlement while preserving the parties’ freedom to choose the means they consider appropriate. It also requires them to exchange views expeditiously when a dispute arises concerning the Convention’s interpretation or application. Negotiation and other diplomatic methods are thus part of the legal structure of dispute settlement, rather than preliminary activities without treaty significance (United Nations, 1982, Arts. 279–283).
Section 2 of Part XV provides for compulsory procedures entailing binding decisions when the applicable conditions have been satisfied and no settlement has been reached through recourse to Section 1. Under Article 287, states may choose among specified judicial and arbitral procedures. Decisions rendered by a court or tribunal with jurisdiction under Section 2 are final and binding between the parties in respect of the particular dispute. Access to those procedures remains subject to the limitations and exceptions in Section 3, including Articles 297 and 298 (United Nations, 1982, Arts. 286–287 and 296–298).
Conciliation differs because its purpose is to assist the parties in reaching an agreement rather than to determine their dispute through a binding judgment or award. Under Annex V, a commission hears the parties, examines their claims and objections, and makes proposals directed toward an amicable settlement. Its report may record an agreement already reached or, failing agreement, set out conclusions on relevant questions of fact or law and recommend possible terms of settlement. Those conclusions and recommendations do not bind the parties (United Nations, 1982, Annex V, Arts. 6–7).
The distinction between voluntary and compulsory conciliation concerns entry into the procedure. Article 284 allows a state party to invite another party to conciliation under Annex V, Section 1, or another procedure. If the invitation is not accepted, or the parties cannot agree on the procedure, that conciliation does not proceed. By contrast, where Section 3 of Part XV authorizes compulsory conciliation, Annex V, Section 2, permits a qualifying party to institute proceedings by written notification. The notified party is obliged to submit, and its failure to respond or participate does not prevent the proceedings from continuing (United Nations, 1982, Art. 284; Annex V, Arts. 11–12).
Compulsory participation does not confer on the commission the authority of an arbitral tribunal. A state can be required to undergo the procedure without being compelled to accept the proposed settlement. Nor does the report’s non-binding character mean that the process is legally inconsequential: the duty to participate derives from UNCLOS, and Article 298 imposes an additional obligation to negotiate on the basis of the report in qualifying maritime delimitation disputes. The legal obligations governing the procedure must be distinguished from the parties’ consent to its substantive outcome (United Nations, 1982, Art. 298(1)(a)(ii); Annex V, Arts. 7 and 11).
2. When UNCLOS Requires States to Enter Conciliation
UNCLOS permits compulsory conciliation only for defined categories of disputes. Article 297 makes the procedure available for specified allegations concerning marine scientific research and fisheries. Article 298 establishes a separate route for certain maritime delimitation disputes involving a state that has made the relevant declaration. These provisions do not create a general entitlement to require conciliation whenever negotiations over maritime rights have failed (United Nations, 1982, Arts. 297–298).
Their legal operation differs. Article 297 limits recourse to binding procedures in relation to particular exercises of coastal-state authority, while preserving conciliation for certain allegations about the exercise of that authority. It does not exclude marine scientific research or fisheries disputes as entire subject areas from adjudication. Article 298 instead allows a state to declare that it does not accept one or more binding procedures for selected categories of disputes. Only the category addressed in Article 298(1)(a), concerning maritime delimitation and historic bays or titles, carries the corresponding obligation to accept compulsory conciliation.
The availability of conciliation consequently depends on the specific dispute and the treaty provision invoked. For research and fisheries, the allegations must fall within the grounds identified in Article 297. For maritime delimitation, the relevant declaration, the timing of the dispute, the absence of a negotiated agreement, and the express exclusions in Article 298 must be considered. The commission’s competence cannot be inferred solely from the fact that a maritime disagreement exists.
2.1 Article 298 and Maritime Boundary Disputes
Article 298(1)(a) permits a state to exclude disputes concerning the interpretation or application of Articles 15, 74, and 83 relating to sea boundary delimitation, as well as disputes involving historic bays or titles, from one or more compulsory procedures entailing binding decisions. The three delimitation provisions concern the territorial sea, exclusive economic zone, and continental shelf, respectively. A declaration determines the procedures the state declines to accept for the specified category; its precise terms remain relevant to the availability of dispute settlement under Part XV (United Nations, 1982, Arts. 15, 74, 83 and 298(1)(a)).
The exclusion is qualified by Article 298(1)(a)(i). When a covered dispute arises after UNCLOS has entered into force and no agreement is reached within a reasonable period through negotiations between the parties, the declaring State must accept submission of the matter to conciliation under Annex V, Section 2, at the request contemplated by the provision. The compulsory obligation arises from UNCLOS when those conditions are met. Making a declaration does not automatically render every dispute within the declared category eligible for conciliation.
The entitlement to initiate proceedings also requires attention to the other paragraphs of Article 298. Paragraph 3 states that a declarant state is not entitled to submit a dispute falling within its excepted category to a procedure under the Convention against another state party without that state’s consent. Paragraph 4 expressly allows another state party to submit a dispute within the excepted category against the declarant state to the procedure specified in the declaration. These provisions qualify the reference in Article 298(1)(a)(i) to a request by any party: it cannot be read in isolation as an unrestricted reciprocal right to initiate proceedings (United Nations, 1982, Art. 298(1)(a)(i) and (3)–(4)).
Paragraph 4 does not dispense with the conditions attached to compulsory conciliation. A dispute must still fall within Article 298(1)(a)(i), satisfy its temporal and negotiation requirements, and avoid its express exclusions. The distinction is illustrated by the Timor Sea proceedings, in which Timor-Leste invoked compulsory conciliation against Australia following Australia’s declaration excluding specified maritime delimitation disputes from binding procedures. Australia contested the commission’s competence, which the commission upheld after examining the applicable conditions (Timor Sea Conciliation Commission, 2016, paras. 42–46 and 65–82).
Even where conciliation proceeds, the commission cannot impose a maritime boundary. Article 298(1)(a)(ii) requires the parties to negotiate an agreement on the basis of its report. If those negotiations fail, submission to a procedure under Part XV, Section 2, requires mutual consent unless the parties otherwise agree. Compulsory conciliation thus preserves a means of third-party assistance while leaving a binding delimitation dependent on an agreement or a separately available adjudicative procedure (United Nations, 1982, Art. 298(1)(a)(ii); Annex V, Art. 7(2)).
2.2 Marine Scientific Research Under Article 297
Coastal states have jurisdiction over marine scientific research in their exclusive economic zones and on their continental shelves, subject to the conditions established by UNCLOS. Article 246 generally requires consent for research in those areas and provides that, in normal circumstances, coastal states shall grant consent to qualifying projects undertaken for peaceful purposes and to increase scientific knowledge of the marine environment. It also identifies grounds on which consent may be withheld at the coastal state’s discretion. Article 253 governs specified circumstances in which research activities may be suspended or ordered to cease (United Nations, 1982, Arts. 246 and 253).
Article 297(2)(a) limits compulsory adjudication of disputes arising from the exercise of the coastal state’s right or discretion under Article 246, or a decision to suspend or cease a project in accordance with Article 253. Article 297(2)(b) nevertheless permits either party to request compulsory conciliation when a researching state alleges that, in relation to a specific project, the coastal state is exercising its rights under those provisions incompatibly with the Convention. The inquiry concerns an identified project and an alleged breach of UNCLOS, rather than a general review of research policy (United Nations, 1982, Art. 297(2)).
The commission cannot call into question the coastal state’s exercise of discretion to withhold consent under Article 246(5), or its discretion to designate specific areas under Article 246(6). The relationship between those provisions requires precision. Article 246(5)(a) permits consent to be withheld where a project is directly significant for the exploration and exploitation of natural resources. Beyond 200 nautical miles on the continental shelf, however, Article 246(6) prevents a coastal state from exercising that particular ground of discretion outside areas it has publicly designated because exploitation or detailed exploratory operations are occurring there or will occur within a reasonable period (United Nations, 1982, Arts. 246(5)(a), 246(6) and 297(2)(b)).
The protection of coastal-state discretion is consequently defined by the Convention itself. A commission cannot replace a protected discretionary choice with its preferred decision, but neither should that limitation be described as an exemption of all research-related conduct from conciliation. The legal inquiry depends on the specific project, the rights invoked, and the compatibility of their exercise with UNCLOS.
2.3 Fisheries Disputes and Coastal-State Discretion
Article 297(3)(a) limits compulsory adjudication of disputes relating to a coastal state’s sovereign rights over living resources in its exclusive economic zone or the exercise of those rights. The provision expressly includes discretionary powers concerning allowable catch, harvesting capacity, allocation of surpluses, and the terms and conditions of conservation and management measures. Other fisheries disputes are not excluded from Part XV, Section 2, simply because they concern living resources (United Nations, 1982, Art. 297(3)(a)).
When settlement has not been reached through recourse to Section 1 of Part XV, Article 297(3)(b) permits a party to request compulsory conciliation on three specified grounds. The first concerns an allegation that a coastal state has manifestly failed to comply with its conservation and management obligations, placing the maintenance of living resources in the exclusive economic zone in serious danger. The reference to manifest failure and serious endangerment makes this ground narrower than an ordinary disagreement over the effectiveness of conservation measures (United Nations, 1982, Art. 297(3)(b)(i)).
The second ground concerns an arbitrary refusal, following another state’s request, to determine the allowable catch and the coastal state’s harvesting capacity for stocks in which the requesting state is interested in fishing. The allegation must concern the refusal identified in Article 297(3)(b)(ii); dissatisfaction with the quantity of an allowable catch does not automatically establish that ground. The distinction is especially relevant where states disagree about fisheries data or access, but the coastal state has made the determinations contemplated by the Convention.
The third ground addresses an arbitrary refusal to allocate to any state all or part of a surplus that the coastal state has declared to exist. It operates subject to Articles 62, 69, and 70 and to conditions established by the coastal state consistently with UNCLOS. The reference to a declared surplus prevents the provision from being treated as a general power for the commission to establish a surplus or redistribute the allowable catch (United Nations, 1982, Art. 297(3)(b)(iii)).
Article 297(3)(c) expressly prohibits the commission from substituting its discretion for that of the coastal state. Its report must also be communicated to the appropriate international organizations under Article 297(3)(d). Compulsory conciliation can address the specified allegations and propose terms of settlement, but it cannot impose the commission’s preferred fisheries-management decisions. The limitations concern the commission’s substantive authority as well as the categories of disputes that may be submitted to it.
3. The Conditions and Limits of Article 298 Conciliation
A maritime delimitation dispute does not become subject to compulsory conciliation solely because the parties have failed to agree on a boundary. Article 298 requires an applicable declaration and satisfaction of the conditions governing disputes within the category specified in paragraph 1(a). It also excludes certain disputes involving unresolved land sovereignty and those already finally settled or covered by a binding agreement for their settlement. These requirements concern the availability of the procedure, not the merits of either party’s proposed boundary (United Nations, 1982, Art. 298(1)(a)).
The declaration’s scope is relevant because Article 298 allows a state to exclude one or more binding procedures for one or more categories of disputes. Its other categories concern specified military and law-enforcement activities and certain disputes before the United Nations Security Council. The compulsory-conciliation obligation associated with maritime delimitation cannot be extended to those categories merely because they appear in the same declaration.
Objections concerning the commission’s competence have their own procedural basis. Annex V, Article 13, authorizes a compulsory conciliation commission to decide disagreements about its competence. A determination that proceedings may continue establishes the commission’s authority to conduct the conciliation; it is not a binding determination of the maritime boundary. The distinction was central to the Timor Sea Commission’s consideration of Australia’s objections in 2016 (United Nations, 1982, Annex V, Arts. 7 and 13; Timor Sea Conciliation Commission, 2016, paras. 42–46).
3.1 Declarations, Negotiations and Temporal Requirements
Article 298(1) permits a state to make its declaration in writing when signing, ratifying, or acceding to UNCLOS, or at any later time. A declaration limits acceptance of the identified procedures for the selected category of disputes but does not displace the obligations of peaceful settlement in Part XV, Section 1. Declarations and notices of withdrawal are deposited with the Secretary-General of the United Nations, who transmits copies to the States Parties (United Nations, 1982, Art. 298(1) and (6)).
For maritime delimitation disputes, Article 298(1)(a)(i) requires the dispute to have arisen after the Convention entered into force. UNCLOS entered into force on November 16, 1994. In its decision on Australia’s objections, the Timor Sea Conciliation Commission interpreted this temporal requirement as referring to the Convention’s entry into force generally, rather than the later date on which it became binding for an individual state. That conclusion was an interpretation reached by the commission in determining its competence, not an amendment to the treaty text (Timor Sea Conciliation Commission, 2016, paras. 69–76).
The provision further requires that no agreement have been reached within a reasonable period through negotiations between the parties. The Timor Sea Commission rejected the proposition that the parties must necessarily have conducted actual boundary negotiations for a prescribed period before conciliation can begin. It reasoned that such a requirement would allow a state to prevent recourse to the procedure simply by refusing to negotiate. The relevant condition is the absence of an agreement within a reasonable period, assessed in the circumstances of the dispute (Timor Sea Conciliation Commission, 2016, paras. 77–82).
This interpretation does not render prior diplomatic conduct irrelevant. The parties’ exchanges, the subject of any negotiations, the passage of time, and the reasons an agreement has not been reached may assist in determining whether Article 298(1)(a)(i) is satisfied. The requirement must also be distinguished from Article 283, which concerns an expeditious exchange of views about settlement by negotiation or other peaceful means. Neither provision should be treated as a mechanical waiting period detached from the parties’ conduct and the dispute’s circumstances (United Nations, 1982, Arts. 283 and 298(1)(a)(i)).
A qualifying dispute must also concern the interpretation or application of the Convention within the declared category. In the Timor Sea proceedings, the commission distinguished a dispute over obligations arising under UNCLOS from one based solely on rights or obligations derived from other sources. The existence of older maritime claims did not, by itself, determine when the dispute concerning the Convention had arisen. Identifying the legal basis and subject of the submitted dispute is accordingly distinct from deciding the merits of the boundary sought by either party (Timor Sea Conciliation Commission, 2016, paras. 69–76).
3.2 Land Sovereignty and Prior Settlement Agreements
Article 298(1)(a)(i) excludes a dispute from compulsory conciliation when addressing it necessarily involves concurrent consideration of an unresolved dispute concerning sovereignty or other rights over continental or insular land territory. Maritime delimitation and territorial sovereignty are legally distinct questions: determining the boundary between maritime entitlements may depend on identifying the state entitled to claim them, but the compulsory-conciliation provision does not grant a commission general authority to settle sovereignty over land (United Nations, 1982, Art. 298(1)(a)(i)).
The exclusion turns on whether concurrent consideration of the unresolved territorial dispute is necessary. The mere existence of a separate disagreement about land territory does not establish that every maritime dispute between the same states is excluded. Equally, a party cannot obtain compulsory conciliation of a territorial sovereignty question simply by presenting it as part of a maritime boundary claim. The connection between the submitted dispute and the unresolved land rights requires a specific assessment.
Article 298(1)(a)(iii) supplies two additional exclusions. The compulsory-conciliation mechanism in paragraph 1(a) does not apply to a sea boundary dispute that the parties have already finally settled by an arrangement. It also does not apply to such a dispute that is to be settled in accordance with a bilateral or multilateral agreement binding on those parties. The latter formulation requires a binding agreement governing settlement of the dispute; it does not require that every settlement method provided by that agreement culminate in a binding judicial or arbitral decision (United Nations, 1982, Art. 298(1)(a)(iii)).
An earlier treaty must consequently be examined for what it actually provides. Arrangements for resource development, provisional cooperation, or postponement of boundary negotiations are not necessarily final boundary settlements or agreements prescribing how the dispute is to be settled. In the Timor Sea proceedings, the Commission considered the parties’ earlier instruments within the framework of Part XV. It concluded that their 2003 exchange of letters did not constitute a legally binding agreement for the purposes of Article 281 and that the 2006 Treaty on Certain Maritime Arrangements in the Timor Sea did not amount to an agreement to seek settlement of the maritime boundary dispute by a chosen peaceful means (Timor Sea Conciliation Commission, 2016, paras. 47–64).
The effect of an earlier agreement cannot be decided merely from its existence or its description as a treaty. Its terms, legal operation, and relationship with UNCLOS determine whether it restricts access to compulsory conciliation. Where the commission finds that it is competent, that finding authorizes the settlement process; it does not itself settle the maritime boundary or invalidate a separate agreement between the parties.
4. The Procedure Under UNCLOS Annex V
Annex V of the United Nations Convention on the Law of the Sea (UNCLOS) establishes the procedure through which a conciliation commission assists states in seeking an agreed settlement. Section 1 contains the general conciliation rules, while Section 2 governs compulsory submission in disputes covered by Part XV, Section 3. Article 14 makes Articles 2–10 of Section 1 applicable to compulsory conciliation, subject to the specific rules in Section 2 (United Nations, 1982, Annex V, Arts. 1–14).
A qualifying party initiates proceedings by notifying the other party. The commission is then constituted, any disagreement concerning its competence may be determined, and the parties are heard. The commission can propose measures that may assist negotiations before presenting its report. Annex V sets rules for each stage but leaves considerable room for the parties and the commission to adapt the process to the dispute.
That flexibility has limits. A state cannot prevent properly instituted compulsory conciliation merely by refusing to participate. Conversely, the commission cannot treat compulsory participation as authority to impose a substantive settlement. Its powers must be understood by reference to both the treaty provisions governing the procedure and the particular dispute submitted to it.
4.1 Initiation and Constitution of the Commission
Under Annex V, Article 11, a party entitled to invoke compulsory conciliation institutes proceedings by written notification addressed to the other party or parties. A party receiving a valid notification is obliged to submit to the procedure. That obligation presupposes that the dispute falls within an applicable compulsory-conciliation provision; notification alone cannot establish the commission’s competence (United Nations, 1982, Annex V, Arts. 11 and 13).
Unless the parties agree otherwise, the commission consists of five conciliators. The initiating party appoints two in its notification, preferably choosing them from the list of conciliators maintained by the Secretary-General of the United Nations. One may be a national of the appointing party. The responding party has 21 days after receiving the notification to appoint two conciliators on the same basis. The four appointees then have 30 days to select a fifth member, drawn from the list, to serve as chair (United Nations, 1982, Annex V, Arts. 2–3).
The appointment rules anticipate a failure to cooperate. If the responding party does not make its appointments within 21 days, the initiating party may, within the following week, terminate the proceedings or request that the Secretary-General make the appointments. If the four conciliators fail to select a chair within the prescribed period, either party may seek the Secretary-General’s intervention within the following week. Appointments made through that mechanism are subject to the requirements of Annex V, Article 3, including consultation with the parties (United Nations, 1982, Annex V, Art. 3(c)–(e)).
The Secretary-General’s appointment and list-maintenance functions should not be confused with the administrative services supplied by a registry. In the Timor Sea conciliation, the Permanent Court of Arbitration (PCA) served as registry for the five-member commission. It provided institutional support but did not itself act as the conciliating body or acquire the Secretary-General’s functions under Annex V (Timor Sea Conciliation Commission, 2018, paras. 47–61).
4.2 Nonparticipation and Objections to Competence
Annex V, Article 12, states that a party’s failure to reply to the notification or submit to conciliation does not bar the proceedings. The rule prevents a notified state from defeating a compulsory process through silence or nonattendance. It does not eliminate the treaty conditions for instituting proceedings or relieve the commission of the need to address a properly raised objection to its competence (United Nations, 1982, Annex V, Arts. 11–13).
Article 13 assigns disagreements about competence to the commission. An objection may concern the existence or subject of the dispute, the scope of an Article 298 declaration, or the effect of an earlier agreement between the parties. Determining competence answers whether the commission may conduct the conciliation. It does not resolve the underlying maritime boundary, research, or fisheries dispute through a binding substantive decision.
Australia raised objections to the commission’s competence at the outset of the Timor Sea proceedings. The commission addressed them as a preliminary matter before beginning sustained settlement discussions. In its 2018 report, it characterized its competence decision as having binding legal effect and explained that the procedural safeguards applied to that decision differed from the more flexible methods used during the subsequent conciliation. This characterization concerned the commission’s decision in those proceedings; it did not make the commission’s eventual settlement recommendations binding (Timor Sea Conciliation Commission, 2018, paras. 65–66).
The distinction affected the conduct of the case. Resolving Australia’s objections established a basis on which both parties could engage with the commission without leaving its authority unresolved throughout negotiations. The commission considered that proceeding otherwise would have impaired the confidence needed for effective conciliation. Its account illustrates why a preliminary determination of competence may be integral to the process, even though the ultimate settlement remains a matter for the parties (Timor Sea Conciliation Commission, 2018, paras. 65–67).
4.3 The Commission's Functions and Final Report
Unless the parties agree otherwise, the Commission determines its own procedure. Article 4 permits it, with the parties’ consent, to invite another state party to submit views orally or in writing. Decisions concerning procedural matters, the report, and recommendations are made by a majority of its members. These rules allow the commission to organize its work around the dispute without dispensing with the parties’ procedural rights (United Nations, 1982, Annex V, Art. 4).
The commission must hear the parties, examine their claims and objections, and make proposals directed toward an amicable settlement. Article 5 also authorizes it to draw attention to measures that could facilitate agreement. Such measures may address obstacles to negotiation before the parties are ready to settle their principal disagreement. The commission’s freedom to propose them does not confer authority to expand its compulsory jurisdiction or impose terms that the parties have not accepted (United Nations, 1982, Annex V, Arts. 5–6).
Article 7(1) sets an ordinary reporting deadline of 12 months from the commission’s constitution. The parties may modify provisions of Annex V by agreement applicable to their dispute under Article 10. The Timor Sea Commission took a separate interpretive step when Australia challenged its competence: it concluded that the 12-month period in those proceedings should run from its decision on competence, issued on September 19, 2016. It reasoned that time required to decide the objection should not deprive the parties of a meaningful opportunity for conciliation. That interpretation was adopted in the particular proceedings, not written into Article 7 as a general exception (Timor Sea Conciliation Commission, 2016, paras. 109–111).
The parties subsequently agreed to extend the Timor Sea proceedings beyond September 2017 because negotiations were progressing. Their agreed extensions were distinct from the commission’s earlier interpretation of the deadline’s starting point. The continued mandate allowed the commission to assist with the treaty negotiations and related discussions concerning Greater Sunrise (Timor Sea Conciliation Commission, 2018, paras. 67–68 and 146).
The report must record agreements reached during conciliation. If the parties have not reached an agreement, it must set out the commission’s conclusions on relevant questions of fact or law and any recommendations it considers appropriate for an amicable settlement. Article 7 requires deposit of the report with the United Nations Secretary-General, who must transmit it immediately to the parties. In maritime delimitation proceedings under Article 298(1)(a), an additional requirement applies: the report must state the reasons on which it is based (United Nations, 1982, Art. 298(1)(a)(ii); Annex V, Art. 7).
Article 8 governs termination of proceedings, including termination upon settlement and specified events following transmission of the report. In the Timor Sea case, the parties expressly agreed to continue the commission’s mandate and extend the reporting period while work on their settlement package remained underway. The maritime boundary treaty was signed in March 2018, and the commission issued its report in May. That sequence reflected the parties’ agreed continuation of the process, rather than an automatic postponement arising from Annex V itself (Timor Sea Conciliation Commission, 2018, paras. 297 and 303–306).
5. The Legal Effect of Compulsory Conciliation
UNCLOS imposes obligations concerning participation in compulsory conciliation, but it does not give a conciliation commission the power to impose its preferred settlement. Annex V, Article 11, obliges a party receiving a valid notification to submit to the proceedings. Article 7(2), by contrast, expressly makes the commission’s report, including its conclusions and recommendations, non-binding (United Nations, 1982, Annex V, Arts. 7 and 11).
The legal effect of a completed conciliation depends partly on the provision under which the proceedings were instituted. Article 298 adds an express obligation to negotiate on the basis of the report in qualifying maritime delimitation disputes. The compulsory-conciliation provisions concerning marine scientific research and fisheries in Article 297 do not prescribe that same post-report sequence.
5.1 The Non-Binding Character of the Report
A conciliation report may address legal and factual questions that are central to a dispute. Its conclusions can inform negotiations and help the parties assess possible terms of settlement. They do not, however, determine the parties’ substantive rights in the manner of a binding judicial decision or arbitral award. A boundary proposed in a report does not become an agreed maritime boundary merely because the commission recommends it (United Nations, 1982, Annex V, Art. 7(1)–(2)).
A determination of competence serves a different function. Annex V, Article 13, empowers the commission to decide whether it may conduct compulsory conciliation. The Timor Sea Commission regarded its preliminary competence decision as having binding legal effect within those proceedings. That decision allowed the process to continue despite Australia’s objections; it did not decide the maritime boundary or require either state to accept particular delimitation terms (Timor Sea Conciliation Commission, 2018, para. 66).
Annex V also anticipates that states may reach an agreement before the report is issued. Article 7(1) directs the commission to record agreements reached during conciliation. An agreement so recorded derives its legal effect from the parties’ consent and its own terms, not from the binding force of the report. In the Timor Sea proceedings, the commission recorded a treaty the parties had already signed rather than imposing a delimitation through its conclusions (Timor Sea Conciliation Commission, 2018, paras. 302–305).
The distinction remains relevant when a commission recommends implementation of an agreement or continued negotiations on an outstanding issue. A recommendation does not independently create the substantive obligation it advocates. Any binding duty must be found in UNCLOS, another applicable legal instrument, or an agreement between the parties.
5.2 Negotiations and the Consequences of Failed Conciliation
Article 298(1)(a)(ii) establishes a further obligation for qualifying maritime delimitation disputes. Once the commission presents its report, which must state the reasons on which it is based, the parties must negotiate an agreement on the basis of that report. The provision makes the report a required point of reference for subsequent negotiations without obliging either state to accept every conclusion or proposed settlement term (United Nations, 1982, Art. 298(1)(a)(ii)).
The duty to negotiate does not guarantee agreement. A state may continue to disagree with the commission’s legal analysis or proposed boundary, provided its conduct remains consistent with its applicable obligations. Compulsory conciliation cannot remove the need for consent to a negotiated delimitation.
Article 298(1)(a)(ii) addresses unsuccessful negotiations expressly. If they do not result in an agreement, the parties are to submit the question to a procedure under Part XV, Section 2, by mutual consent, unless they otherwise agree. The mutual-consent requirement is decisive: failed conciliation does not, by itself, give either party a right to initiate binding adjudication unilaterally under that provision. Any jurisdiction asserted through another legal basis must be assessed on its own terms.
Compulsory conciliation under Article 297(2)(b) or 297(3)(b) has different consequences. Those provisions permit specified research and fisheries disputes to be submitted to a commission, but neither reproduces Article 298’s express post-report negotiation and mutual-consent provisions. The commission’s report remains non-binding under Annex V, while any continuing obligations concerning research, conservation, fisheries access, or peaceful settlement retain their separate legal bases.
6. The Timor Sea Conciliation: Procedure in Practice
On April 11, 2016, Timor-Leste instituted compulsory conciliation against Australia under Article 298(1)(a)(i) and Annex V, Section 2. The dispute concerned the delimitation of permanent maritime boundaries in the Timor Sea. Earlier instruments regulated petroleum activities and aspects of the parties’ relationship without establishing a comprehensive permanent maritime boundary (Timor Sea Conciliation Commission, 2018, paras. 1–2 and 14–46).
The proceedings were conducted by a five-member commission with the PCA acting as registry. Australia objected to the commission’s competence, requiring a preliminary determination before the parties proceeded to substantive settlement discussions. Once the commission upheld its competence, it worked with both governments through meetings, written exchanges, and proposals intended to make an agreed boundary possible (Timor Sea Conciliation Commission, 2018, paras. 47–68).
The negotiations extended to matters closely connected with delimitation, including transitional petroleum arrangements and the Greater Sunrise fields. Their inclusion reflected the parties’ efforts to reach an acceptable settlement package. It did not transform the Commission into a tribunal empowered to decide those matters without the states’ agreement.
6.1 The Commission's Decision on Competence
Australia challenged the Commission’s competence on grounds relating to the parties’ earlier agreements, the timing of the dispute, and the negotiation requirement in Article 298. The Commission heard those objections as a preliminary matter and issued its decision on September 19, 2016. It concluded that it was competent to conduct the conciliation and that no issue of admissibility or comity prevented the proceedings from continuing (Timor Sea Conciliation Commission, 2016, paras. 39–46 and 111).
The decision distinguished agreements regulating the parties’ conduct in the Timor Sea from agreements that would preclude recourse to the Convention’s dispute-settlement procedures. The commission concluded that the earlier instruments on which Australia relied did not prevent compulsory conciliation. Its task was to determine the effect of those instruments on its competence, not to rule on the validity of the 2006 Treaty on Certain Maritime Arrangements in the Timor Sea, which had been contested in separate proceedings (Timor Sea Conciliation Commission, 2016, paras. 47–64 and 83–92).
The commission also interpreted Article 298(1)(a)(i)’s temporal requirement as referring to UNCLOS’s entry into force generally, rather than its later entry into force for an individual state. In considering the negotiation requirement, it rejected an approach that would allow one party to prevent conciliation indefinitely by refusing to negotiate. These conclusions addressed the conditions for initiating the procedure; they did not determine the merits of either party’s proposed maritime boundary (Timor Sea Conciliation Commission, 2016, paras. 69–82).
A final procedural question concerned the reporting deadline. The commission decided that the 12-month period under Annex V, Article 7, would run from its September 2016 decision on competence. It considered that an unresolved objection should not consume the time available for substantive conciliation. The parties later agreed to extend the proceedings further. The commission’s interpretation of the starting date and the parties’ subsequent agreement to extend the deadline were separate steps (Timor Sea Conciliation Commission, 2016, paras. 109–111; 2018, paras. 67–68).
6.2 Negotiations, the Maritime Treaty and the Final Report
After the competence decision, the commission addressed obstacles to negotiations, including the relationship between the boundary dispute and existing petroleum arrangements. It proposed confidence-building measures and met with the parties jointly and separately. Those methods allowed each government to explain its position while the commission identified terms on which a wider agreement might become possible (Timor Sea Conciliation Commission, 2018, paras. 88–106).
On August 30, 2017, Timor-Leste and Australia reached a comprehensive package agreement covering maritime boundaries, arrangements concerning Greater Sunrise, and steps toward a formal treaty. The commission and the parties agreed to continue the proceedings beyond the original timetable while the treaty was finalized and related discussions proceeded. The extended mandate also allowed the commission to assist with negotiations concerning a development concept for Greater Sunrise (Timor Sea Conciliation Commission, 2018, paras. 146, 164 and 297).
The states signed the Treaty Establishing Their Maritime Boundaries in the Timor Sea on March 6, 2018. It established agreed maritime boundaries and a special regime for Greater Sunrise. The treaty entered into force on August 30, 2019, following an exchange of notes between the states’ prime ministers. Its entry into force is confirmed by Australia’s Department of Foreign Affairs and Trade, rather than by the commission’s report, which preceded that event (Timor Sea Conciliation Commission, 2018, para. 304; Australian Department of Foreign Affairs and Trade, n.d.).
The commission issued its report and recommendations on May 9, 2018. It recorded the parties’ agreement to extend its mandate and reporting period, as well as the maritime boundary treaty they had signed. The commission recommended implementation of the agreements reached, including transitional arrangements. It also recommended further discussions on a development concept for Greater Sunrise, which remained unresolved when the report was issued (Timor Sea Conciliation Commission, 2018, paras. 297 and 303–306).
The proceedings demonstrate the different legal functions performed by the commission and the parties. The commission determined objections to its competence and assisted negotiations; Timor-Leste and Australia agreed on the boundary and concluded the treaty. The case illustrates how compulsory conciliation can lead to a binding settlement through state consent. Its outcome does not establish that every dispute submitted under Annex V will end in agreement.
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Conclusion
UNCLOS compulsory conciliation requires States Parties to participate in a defined settlement procedure when the conditions in Articles 297 or 298 are satisfied. Annex V supplies the rules for constituting a commission, conducting proceedings despite nonparticipation, determining disagreements about competence, and issuing a report. The commission’s substantive conclusions and recommendations remain non-binding.
For qualifying maritime delimitation disputes, Article 298 adds a duty to negotiate on the basis of a reasoned report. Failed negotiations do not independently authorize unilateral referral to binding adjudication under that provision; submission requires mutual consent unless the parties otherwise agree. The research and fisheries provisions in Article 297 do not contain the same post-report sequence.
The Timor Sea conciliation shows the legal distinction in operation. The commission could conduct the procedure despite Australia’s challenge to its competence, but it did not impose the eventual boundary. Timor-Leste and Australia established that boundary by treaty. Compulsory conciliation can require states to engage in settlement efforts; a binding substantive agreement remains dependent on the legal basis through which the states accept it.
References
Australian Department of Foreign Affairs and Trade (n.d.) Australia’s maritime arrangements with Timor-Leste [online]. Available at: https://www.dfat.gov.au/geo/timor-leste/australias-maritime-arrangements-with-timor-leste (Accessed: 9 September 2026).
Timor Sea Conciliation Commission (2016) Decision on Australia’s Objections to Competence, 19 September, Reports of International Arbitral Awards, vol. XXXIV, p. 205 [online]. Available at: https://legal.un.org/riaa/cases/vol_XXXIV/205-464.pdf (Accessed: 10 September 2026).
Timor Sea Conciliation Commission (2018) Report and Recommendations of the Compulsory Conciliation Commission between Timor-Leste and Australia on the Timor Sea, 9 May, Reports of International Arbitral Awards, vol. XXXIV, p. 245 [online]. Available at: https://legal.un.org/riaa/cases/vol_XXXIV/205-464.pdf (Accessed: 10 September 2026).
Treaty between Australia and the Democratic Republic of Timor-Leste Establishing Their Maritime Boundaries in the Timor Sea (2018) signed 6 March 2018, entered into force 30 August 2019, [2019] ATS 16.
United Nations Convention on the Law of the Sea (1982) adopted 10 December 1982, entered into force 16 November 1994, 1833 UNTS 3.
