About the Author: LCDR Stephen S Pagcaliwagan is a Philippine Coast Guard Officer who completed his master’s degree in security studies (Homeland Security and Defense) from the Naval Postgraduate School in Monterey, California. His master’s thesis explored Indonesia’s experience with its archipelagic sea lane and analyzed its implications for the Philippines as it develops its nascent archipelagic sea lanes management strategy.
In 2024, the Philippines became just the second country in the world to designate archipelagic sea lanes (ASLs). To help the Philippines strategically plan the management of its newly designated archipelagic sea lanes, an examination of Indonesia’s rich experience in designating and managing its ASLs is crucial. Indonesia’s experience with the Alur Laut Kepulauan Indonesia (ALKI) offers a robust framework for understanding the multifaceted challenges and opportunities that the Philippines can use as a head start. What strategic benefits do ASLs provide? More importantly, what lessons can the Philippines draw from Indonesia’s experience to develop an effective ASL management strategy?
ASLs for Archipelagic National Security
For archipelagos with multiple sea lines of communication, designating ASLs provides three vital benefits for archipelagic national security. Firstly, the designation of ASLs enhances legal clarity in maritime enforcement by allowing archipelagic states to segregate which of their waters are navigable by innocent passage or archipelagic sea lanes passage.[1] Second, by delineating the waters subject to each type of passage, archipelagic states can more effectively and strategically deploy surveillance resources to monitor adherence to passage regulations.[2] By allowing ships and planes to use designated ASLs in their normal modes, the ASL framework simplifies how international maritime and air traffic move through these routes, steering them away from less optimal alternatives. Altogether, this approach improves operational efficiency for maritime authorities.
States that use archipelagic waters also benefit from ASLs. They provide defined corridors for international navigation, reducing uncertainty and potential conflicts within a state’s sovereign waters. Also, navigating through designated ASLs ensures unobstructed transit within archipelagic waters, thus upholding freedom of navigation and ensuring economic efficiency for merchant and military vessels.[3] Moreover, navigating in the normal mode is paramount for the covert transit of military submarines, which is essential for the deterrent posture of maritime powers.[4]
Not designating ASLs is particularly disadvantageous for archipelagic states since ships and aircraft can continue to navigate in their normal mode in all other routes “normally used for international navigation.”[5] Normally, ships and aircraft can enjoy archipelagic sea lanes passage, and the state cannot suspend this unless it designates its own ASLs.[6] Without ASLs, foreign submarines can stay submerged during transit, and foreign aircraft can exercise overflight in all international sea routes normally used by all user states within the archipelago’s maritime domain
The Indonesian Experience
Indonesian ASLs, known as Alur Laut Kepulauan Indonesia (ALKI), were approved by the IMO in 1998.[7] The process of designating ASLs started with national surveys and interagency coordination from 1994 to 1995.[8] In 1996, Indonesia held consultations with the International Hydrographic Organization (IHO) and with interested user states, such as the United States, Australia, Japan, and the United Kingdom.[9] In 1998, the IMO accepted Indonesia’s ASLs, but only considered it as a partial ASL proposal.[10] Buntoro states that the IMO’s adoption of the ALKI and the enactment of Government Regulation Number 37 of 2002 could be considered a “first State of practice on the archipelagic sea lanes passage” to balance Indonesia’s interests with the user States.[11] As Indonesia took measures to unlock the benefits of the archipelagic regime by designating ASLs, it faced several challenges.
Lengthy Designation Process
First in the list is the protracted designation process. This protraction is mainly caused by Indonesia’s dilemma in satisfying the interests of all user States while maintaining the number of ASLs at a manageable level—and this series of negotiations with various States and international institutions started from 1994 up until the IMO’s approval in 1998. A primary issue for user states regarding Indonesia’s archipelagic waters was that its proposed ASLs did not include an east-west route. Several maritime powers, including Australia and the United States, argued that Indonesia did not meet the requirement to include “all normal passage routes used as routes for international navigation” pursuant to Article 53 of the 1982 UNCLOS.[12] Australia particularly objected to Indonesia’s proposal, considering its strategic requirement for a non-suspended east-west route through the archipelago, which the Royal Australian Navy consistently traverses.[13]
Moreover, Buntoro observed that at least three maps showed the normal routes for international navigation and overflight that can be considered for the designation of Indonesia’s ASLs: the British Admiralty Chart, the United States Chart, and the Australian Chart.[14] Djalal notes that the routes on these charts varied greatly, making it impossible for Indonesia to designate routes that meet all user States’ interests.[15] If Indonesia were to designate all sea lanes as archipelagic sea lanes, Buntoro contended that there would appear to be no difference between innocent passage and archipelagic sea lanes passage.[16] Despite the time and effort Indonesia invested, the IMO only considered the ALKI a partial designation because it failed to include all normal passage routes for international navigation and overflight. As seen in Indonesia’s experience, since the completeness of an ASL designation requires the inclusion of all normal passage routes as claimed by all interested user States, Batongbacal argued that the completeness of a designation is therefore the prerogative of user States to decide, rather than the archipelagic state.[17] Since Indonesia’s ASLs, that being a “partial” designation, did not prevent the exercise of ASLP in other undesignated routes, Batongbacal finds that a partial designation is like no designation at all.[18]
Fragmented Maritime Oversight
Poor coordination among maritime security concerned agencies limits Indonesia’s effective management of its ASLs.[19] The creation of the Coordinating Agency for Maritime Security (BAKORKAMLA), and consequently, the Indonesian Maritime Security Agency (BAKAMLA), were efforts to address this challenge. Sodik states that overlapping jurisdictions that deal with maritime affairs exist among the Indonesian Navy, Air Force, Marine Police, the Ministry of Marine and Fisheries Affairs, and the Ministry of Foreign Affairs.[20] He added that despite BAKORKAMLA’s purpose of coordinating all maritime security agencies, it was unable to reduce the maritime violations in Indonesia in the past 30 years. This dilemma is emphasized by Dirhamsyah through incidents of oil spills in the Seribu Islands since 2003.[21] In an oil spill in 2004, it was examined that the Ministry of Maritime Affairs and Fisheries (MOMAF), the State Ministry of Environment, and the Marine National Park of Seribu Islands conducted separate investigations, none of which resulted in any prosecution.[22]
To overcome red tape and boost effectiveness in maritime law enforcement, the BAKORKAMLA was given a new legal basis and a broader maritime security mandate in 2014 with the creation of the Indonesian Maritime Security Agency (BAKAMLA).[23] In February 2020, President Joko Widodo expressed that the BAKAMLA “will be the embryo of an Indonesian coast guard,” having overarching authority over maritime safety and security.[24] However, Darmawan alleges that Indonesia’s maritime law enforcement remains fragmented due to the strong political resistance from agencies that currently have the capacity for maritime law enforcement, who fear budget cuts from the restructuring of relevant government agencies.[25] To cover Indonesia’s vast maritime domain and compensate for its lack of vessels, the BAKAMLA concentrates its efforts on coordinating patrols across agencies – but information sharing among agencies is still lacking.[26]
Limited Surveillance and Enforcement Capability
Indonesia has limited maritime law enforcement capabilities to manage its ASLs, mainly due to manpower and facility deficits. Arsana, Supriyanto, and Sebastian state that Indonesia lacks adequately skilled personnel and equipment to oversee its maritime boundaries.[27] Laksamana and Supriyanto concur by stating that Indonesia’s civilian maritime law enforcement agencies are underfunded, underequipped, and understaffed.[28] Sodik also argues that Indonesia’s limited and poorly maintained warships and patrol vessels hinder its ability to detain foreign vessels.[29] In 2017, 58% of vessels were transiting outside of the ALKI boundaries, highlighting gaps in surveillance and enforcement capability.[30]
High Vulnerability
Lastly, Indonesia remains significantly vulnerable to belligerent forces. This challenge stems from the IMO’s decision that the ALKI is only a partial designation.[31] With this, ships and aircraft, including foreign military forces, are not restricted from exercising archipelagic sea lanes passage in their normal modes on all other routes they used before Indonesia’s designation.[32] Foreign military submarines can remain submerged, and aircraft carriers, their protecting vessels, and aircraft can navigate in formation. As they enjoy this passage regime, they cannot be obstructed by the archipelagic state.[33] Bautista and Yoga assumed that Indonesia’s ASLs were already significantly vulnerable to submarines due to their breadth and depth,[34] and now this challenge has become more profound as submarines can remain undetected throughout its waters.
Conclusion
Indonesia’s experience offers four key lessons for the Philippines as it develops its ASL management strategy.
Anticipating a Protracted and Complex Designation Process
The Philippines should anticipate a complex and time-consuming negotiation phase when seeking international recognition for its own ASLs, as evidenced by Indonesia’s lengthy diplomatic efforts to secure its ASL designations. This process underscores the critical importance of a robust, well-articulated proposal that meticulously addresses international navigation requirements and existing maritime conventions. Furthermore, the Indonesian experience highlights the geopolitical pressures and strategic considerations that influence the designation and acceptance of ASLs, necessitating a comprehensive understanding of global maritime interests beyond mere legal compliance.[35] This prolonged negotiation period also underscores the inherent tension between an archipelagic state’s sovereignty over its internal waters and the international community’s insistence on unimpeded navigation, particularly for military vessels, necessitating strategic diplomacy and legal acumen from the Philippines.
Prioritizing Investment in Robust Surveillance and Enforcement Capabilities
Indonesia’s limited enforcement capabilities resulted in a high percentage of vessels transiting outside designated sea lane boundaries, demonstrating that legal designations alone are insufficient without the physical means to monitor and regulate compliance.[36] Hence, the Philippines, with its similarly constrained naval and coast guard resources, must prioritize significant investment in advanced surveillance technologies, naval assets, and specialized capabilities to detect transiting submarines exercising ASLP and enforce submarine compliance with innocent passage requirements in archipelagic waters outside designated ASLs.
Fostering Cohesive Maritime Security Governance
Indonesia’s case reveals that fragmented maritime security governance, characterized by overlapping jurisdictions and inter-agency rivalry among its many agencies, leads to operational inefficiencies and surveillance gaps.[37] As the Philippines mirrors this fragmentation, this underscores the imperative for a cohesive inter-agency collaboration to ensure a unified and effective approach to managing the complexities of ASLs, thereby mitigating vulnerabilities, upholding archipelagic national security, and ensuring unimpeded international navigation and overflight over ASLs. Therefore, a streamlined command structure and clear delineation of roles and responsibilities are essential for the Philippines to overcome potential bureaucratic hurdles, facilitate real-time data sharing, and coordinated response in managing ASLs.
Completely Designating ASLs
Indonesia’s experience shows that a partial designation, such as the absence of an east-west sea lane through the Java Sea, leaves the archipelagic state vulnerable to challenges from foreign military forces asserting rights of transit through routes normally used for international navigation.[38] This rendered the ASL designation useless, since foreign military vessels could continue to exercise the right of ASLP through undesignated routes. It is therefore paramount for the Philippines to secure a complete ASL designation by carefully considering the maritime interests of all user states while delicately balancing the Philippines’ national security needs. This requires meticulous statesmanship and diplomatic prowess to navigate the intricate geopolitical landscape effectively.
Recommendations
In addition to the insights gained from Indonesia’s ASL experience, this paper proposes the following recommendations.
Exploring Advanced Submarine Detection Systems
Both the PCG and PN fleets’ prospective expansion should address the limitations of their land-based sensors, including the detection of any “dark activity” that escapes the purview of traditional radar and AIS systems within the archipelagic sea lanes. To expand the Philippines’ maritime domain awareness capability and ensure the compliance of submarine transit with ASLP and innocent passage requirements, it may be worthwhile to explore the feasibility of adopting advanced submarine detection systems, such as Sound Surveillance Systems (SOSUS).[39] These systems could be embedded in navigational buoys around key areas in the archipelagic sea lanes and all other strategic routes. Should this strengthened maritime security posture come to fruition, it would also improve archipelagic defense against non-traditional threats such as illicit drug and firearms trade, human trafficking, piracy, armed robbery at sea, and illegal, unregulated and unreported fishing.
Developing an ASL Management Strategy and Fostering Interagency Synergy
Effectively managing ASLs calls for the development of an ASL management strategy. This strategy will not only require significant improvements in an archipelagic state’s maritime forces but also call for interagency synergy since ships and aircraft exercising ASLP in these sea lanes have archipelagic national security and geopolitical implications. The complex interplay of these factors necessitates a robust, unified command structure to ensure seamless information sharing and coordinated response across all relevant government agencies. This integrated approach would enable the Philippines to effectively monitor, regulate, and respond to activities within its ASLs, thereby safeguarding its national interests while upholding international maritime norms. Furthermore, adopting a comprehensive interagency strategy, potentially involving joint patrols and shared intelligence platforms, could significantly enhance the Philippines’ capacity to enforce regulations and address emergent threats within its designated ASLs.
Strengthen Maritime Security Posture through Enhanced U.S.–Philippine Cooperation
As an enhanced Philippine ASL management strategy potentially escalates geopolitical tensions in the region, with the possible contention of certain states such as China, this challenge calls for an integrated, multi-faceted diplomatic approach that includes proactive engagement with regional partners and international bodies to build consensus and uphold the principles of UNCLOS. One of these treaty allies would be the United States, which has expressed interest in supporting the Philippines’ maritime security efforts. A strengthened maritime security posture through enhanced U.S.-Philippine cooperation would bolster the Philippines’ capacity for ASL surveillance, information sharing, and enforcement. This collaboration would also serve to deter potential infringements on the Philippines’ maritime domain and ensure the safe passage of legitimate maritime traffic through its archipelagic waters, while simultaneously strengthening regional stability and adherence to international law.
References:
Adoption of Amendments to the General Provisions on Ships’ Routeing (Resolution A.572 (14) As Amended), Pub. L. No. Resolution MSC.71(69), Annex 9 (1998).
“Archipelagic States and Maritime Navigation: Perspectives and State Practice of the Philippines.” In Regulation on Navigation of Foreign Vessels: Asia-Pacific State Practice, 1st ed., vol. 6, by Jay L. Batongbacal, 115–27. Brill | Nijhoff, 2019. https://doi.org/10.1163/9789004396272_008.
Arsana, I. Made Andi, Ristian A. Supriyanto, and Leonard Sebastian. “Indonesia and the Law of the Sea: Beyond the Archipelagic Outlook.” National Security College Issue Brief, May 9, 2014, 67–76.
Baiquni, Muhammad, Mohammad P. Hadi, and Fika Monika. “Foreign Vessels’ Mobility Crossing the Archipelagic Sea Lanes in the Karimata Strait.” AACL Bioflux 15, no. 4 (2022).
Batongbacal, Jay. “Barely Skimming the Surface: Archipelagic Sea Lanes Navigation and the IMO.” In Oceans Management in the 21st Century: Institutional Frameworks and Responses, 49–68. Brill Nijhoff, 2004.
Bautista, Lowell, and Pornomo Rovan Astri Yoga. “Legal Analysis of the Establishment of Exclusion Zones for Submarines in Indonesia’s Archipelagic Sea Lanes.” Ocean Development & International Law, July 14, 2025, 1–29. https://doi.org/10.1080/00908320.2025.2529801.
Beckman, Robert. “Archipelagic Sea Lanes Passage in Southeast Asia.” In Maritime Security in Southeast Asia. Routledge, 2007. https://doi.org/10.4324/9780203964415.
Buntoro, Kresno. “Legal and Technical Issues on Designating Archipelagic Sea Lanes Passage: Indonesia Experience.” Indonesian Journal of International Law 8, no. 2 (April 2011). https://doi.org/10.17304/ijil.vol8.2.2.
Cay, Vivien Jane Evangelio. “Archipelagic Sea Lanes Passage and Maritime Security in Archipelagic Southeast Asia.” World Maritime University, 2010.
Darmawan, Aristyo Rizka. “Indonesia’s maritime law enforcement faces troubled waters.” East Asia Forum, August 9, 2020. https://eastasiaforum.org/2020/08/29/indonesias-maritime-law-enforcement-faces-troubled-waters/.
Dirhamsyah. “Maritime Law Enforcement and Compliance in Indonesia: Problems and Recommendations.” Maritime Studies 2005, no. 144 (September 2005): 1–16. https://doi.org/10.1080/07266472.2005.10878790.
Gallaga, Moira G. “Designating Archipelagic Sea Lanes.” Philippine Daily Inquirer, November 10, 2022. https://opinion.inquirer.net/158602/designating-archipelagic-sea-lanes.
General Provisions for the Adoption, Designation and Substitution of Archipelagic Sea Lanes, Pub. L. No. MSC.72(69) (1998).
Laksmana, Evan A., and Ristian A. Supriyanto. “Abandoned at Sea: The Tribunal Ruling and Indonesia’s Missing Archipelagic Foreign Policy.” Asian Politics & Policy 10, no. 2 (April 2018): 300–321. https://doi.org/10.1111/aspp.12393.
Oegroseno, Arif Havas. “Archipelagic Sea Lanes Passage Designation: The Indonesian Experience.” In Freedom of Seas, Passage Rights and the 1982 Law of the Sea Convention, edited by Myron H. Nordquist, Tommy Koh, and John Norton Moore, 383–91. Brill | Nijhoff, 2009. https://doi.org/10.1163/ej.9789004173590.i-624.123.
Puspitawati, Dhiana. “Indonesia’s Archipelagic Sea Lanes (ASLs) Designation: Rights Turning to Obligations?” Hasanuddin Law Review 4, no. 3 (December 2018): 265. https://doi.org/10.20956/halrev.v4i3.1488.
Saragih, Bagus. “New Maritime Body Ready to Set Sail.” The Jakarta Post (Batam, Riau Islands), December 12, 2014. https://www.thejakartapost.com/news/2014/12/12/new-maritime-body-ready-set-sail.html.
Sodik, Dikdik Mohamad. “The Indonesian Legal Framework on Baselines, Archipelagic Passage, and Innocent Passage.” Ocean Development & International Law 43, no. 4 (October 2012): 330–41. https://doi.org/10.1080/00908320.2012.726830.
Trang, Pham Ngoc Minh. “Balancing Navigational Rights of Ships and Maritime Security of Coastal States: The Case of Designating Archipelagic Sea Lanes of Indonesia and the Philippines.” Asia-Pacific Journal of Ocean Law and Policy 7, no. 2 (December 2022): 260–79. https://doi.org/10.1163/24519391-07020006.
United Nations Convention on the Law of the Sea, 1982 (1982).
[1] “Archipelagic States and Maritime Navigation: Perspectives and State Practice of the Philippines,” in Regulation on Navigation of Foreign Vessels: Asia-Pacific State Practice, 1st ed., vol. 6, by Jay L. Batongbacal (Brill | Nijhoff, 2019), 120–21, https://doi.org/10.1163/9789004396272_008.
[2] Moira G. Gallaga, “Designating Archipelagic Sea Lanes,” Philippine Daily Inquirer, November 10, 2022, https://opinion.inquirer.net/158602/designating-archipelagic-sea-lanes.
[3] Robert Beckman, “Archipelagic Sea Lanes Passage in Southeast Asia,” in Maritime Security in Southeast Asia (Routledge, 2007), 120, https://doi.org/10.4324/9780203964415.
[4] “Archipelagic States and Maritime Navigation,” 121.
[5] United Nations Convention on the Law of the Sea, 1982 (1982), 43.
[6] United Nations Convention on the Law of the Sea, 1982, 43.
[7] Dhiana Puspitawati, “Indonesia’s Archipelagic Sea Lanes (ASLs) Designation: Rights Turning to Obligations?,” Hasanuddin Law Review 4, no. 3 (December 2018): 275, https://doi.org/10.20956/halrev.v4i3.1488.
[8] Arif Havas Oegroseno, “Archipelagic Sea Lanes Passage Designation: The Indonesian Experience,” in Freedom of Seas, Passage Rights and the 1982 Law of the Sea Convention, ed. Myron H. Nordquist, Tommy Koh, and John Norton Moore (Brill | Nijhoff, 2009), 389, https://doi.org/10.1163/ej.9789004173590.i-624.123.
[9] Oegroseno, 389.
[10] Vivien Jane Evangelio Cay, “Archipelagic Sea Lanes Passage and Maritime Security in Archipelagic Southeast Asia” (World Maritime University, 2010), 44.
[11] Kresno Buntoro, “Legal and Technical Issues on Designating Archipelagic Sea Lanes Passage: Indonesia Experience,” Indonesian Journal of International Law 8, no. 2 (April 2011): 220, https://doi.org/10.17304/ijil.vol8.2.2.
[12] Dikdik Mohamad Sodik, “The Indonesian Legal Framework on Baselines, Archipelagic Passage, and Innocent Passage,” Ocean Development & International Law 43, no. 4 (October 2012): 335, https://doi.org/10.1080/00908320.2012.726830.
[13] Sodik, 335.
[14] Buntoro, “Legal and Technical Issues on Designating Archipelagic Sea Lanes Passage,” 230–31.
[15] “Archipelagic States and Maritime Navigation,” 122.
[16] Buntoro, “Legal and Technical Issues on Designating Archipelagic Sea Lanes Passage,” 232.
[17] “Archipelagic States and Maritime Navigation,” 122.
[18] Jay Batongbacal, “Barely Skimming the Surface: Archipelagic Sea Lanes Navigation and the IMO,” in Oceans Management in the 21st Century: Institutional Frameworks and Responses (Brill Nijhoff, 2004), 55.
[19] Evan A. Laksmana and Ristian A. Supriyanto, “Abandoned at Sea: The Tribunal Ruling and Indonesia’s Missing Archipelagic Foreign Policy,” Asian Politics & Policy 10, no. 2 (April 2018): 311, https://doi.org/10.1111/aspp.12393.
[20] Sodik, “The Indonesian Legal Framework on Baselines, Archipelagic Passage, and Innocent Passage,” 337.
[21] Dirhamsyah, “Maritime Law Enforcement and Compliance in Indonesia: Problems and Recommendations,” Maritime Studies 2005, no. 144 (September 2005): 6–7, https://doi.org/10.1080/07266472.2005.10878790.
[22] Dirhamsyah, 7.
[23] Bagus Saragih, “New Maritime Body Ready to Set Sail,” The Jakarta Post (Batam, Riau Islands), December 12, 2014, https://www.thejakartapost.com/news/2014/12/12/new-maritime-body-ready-set-sail.html.
[24] Aristyo Rizka Darmawan, “Indonesia’s maritime law enforcement faces troubled waters,” East Asia Forum, August 9, 2020, https://eastasiaforum.org/2020/08/29/indonesias-maritime-law-enforcement-faces-troubled-waters/.
[25] Darmawan.
[26] Darmawan.
[27] I. Made Andi Arsana, Ristian A. Supriyanto, and Leonard Sebastian, “Indonesia and the Law of the Sea: Beyond the Archipelagic Outlook,” National Security College Issue Brief, May 9, 2014, 73.
[28] Laksmana and Supriyanto, “Abandoned at Sea,” 311.
[29] Sodik, “The Indonesian Legal Framework on Baselines, Archipelagic Passage, and Innocent Passage,” 337.
[30] Muhammad Baiquni, Mohammad P. Hadi, and Fika Monika, “Foreign Vessels’ Mobility Crossing the Archipelagic Sea Lanes in the Karimata Strait,” AACL Bioflux 15, no. 4 (2022): 1727.
[31] Adoption of Amendments to the General Provisions on Ships’ Routeing (Resolution A.572 (14) As Amended), Pub. L. No. Resolution MSC.71(69), Annex 9 (1998).
[32] General Provisions for the Adoption, Designation and Substitution of Archipelagic Sea Lanes, Pub. L. No. MSC.72(69) (1998), Article 6.7.
[33] Pham Ngoc Minh Trang, “Balancing Navigational Rights of Ships and Maritime Security of Coastal States: The Case of Designating Archipelagic Sea Lanes of Indonesia and the Philippines,” Asia-Pacific Journal of Ocean Law and Policy 7, no. 2 (December 2022): 265, https://doi.org/10.1163/24519391-07020006.
[34] Lowell Bautista and Pornomo Rovan Astri Yoga, “Legal Analysis of the Establishment of Exclusion Zones for Submarines in Indonesia’s Archipelagic Sea Lanes,” Ocean Development & International Law, July 14, 2025, 8, https://doi.org/10.1080/00908320.2025.2529801.
[35] Puspitawati, “Indonesia’s Archipelagic Sea Lanes (ASLs) Designation,” 278.
[36] Baiquni, Hadi, and Monika, “Foreign Vessels’ Mobility Crossing the Archipelagic Sea Lanes in the Karimata Strait,” 1727.
[37] Sodik, “The Indonesian Legal Framework on Baselines, Archipelagic Passage, and Innocent Passage,” 337.
[38] Bautista and Yoga, “Legal Analysis of the Establishment of Exclusion Zones for Submarines in Indonesia’s Archipelagic Sea Lanes,” 8.
[39] Bautista and Yoga, 8–9.