In a significant step towards strengthening maritime security in Southeast Asia, Japan has deepened its partnership with Indonesia through joint anti-piracy exercises and the donation of high-speed patrol boats. The Japan Coast Guard (JCG) patrol vessel Settsu recently docked at Tanjung Priok Port in Jakarta on 24 January 2025, following collaborative drills with the Indonesia Coast Guard (BAKAMLA). This marks the JCG’s 50th deployment to the region since 2000, underscoring Tokyo’s long-standing commitment to countering piracy and enhancing regional stability.
Beyond the exercises, Japan has donated two state-of-the-art patrol boats to Indonesia under its Official Security Assistance (OSA) programme. These vessels, described as “brand-new and made in Japan” by Indonesian Defense Minister Sjafrie Samsoeddin, are set to be deployed off the coast of Nusantara, Indonesia’s future capital in East Kalimantan. The boats, each 5 metres wide and 18 metres long, boast diesel engines with a top speed of 40 knots and can carry up to 16 personnel. The Indonesian government plans to equip them with weaponry, further bolstering maritime security at critical choke points.
“The Navy chief of staff told me that the patrol boats are to be deployed in Nusantara waters to secure our maritime choke points,” Sjafrie told a meeting with House of Representatives Commission I, as quoted by Kompas.com on 6 February 2025. He added that Japan’s initiative reflects its desire to showcase domestic shipbuilding capabilities, a gesture Indonesia respects. 
The deal for the patrol boats was sealed during a bilateral meeting last month between Indonesian President Prabowo Subianto and Japanese Prime Minister Shigeru Ishiba. The leaders also agreed to sustain “two-plus-two” dialogues between their foreign and defence ministers and to establish a maritime security forum focused on defence equipment cooperation and technology transfer. These agreements signal a broader strategic alignment between Jakarta and Tokyo, particularly in the context of growing regional tensions.
A Strategic Move in the Indo-Pacific
When Japan has security concerns of its own with Norht Korea’s firing of missiles over japanese air space and China’s push into the near-by Taiwan Strait, you might be wondering why Japan is seeking involvement in the Indo-Pacific. Japan’s engagement with Indonesia forms part of a wider strategy to counterbalance China’s assertive territorial claims in the Indo-Pacific, particularly in the South China Sea. While Indonesia is not a direct claimant in the long-standing dispute over this vital waterway—through which an estimated $3 trillion in trade passes annually—it has faced repeated incursions by Chinese naval and fishing vessels in adjacent waters, notably around the Natuna Islands. These encounters have heightened Jakarta’s interest in fortifying its maritime presence, even as it maintains a neutral stance in the broader geopolitical contest.
Japan, a close ally of the United States, has openly expressed concern over Beijing’s near-total claim to the South China Sea, which overlaps with territories disputed by Vietnam, the Philippines, Malaysia, and Brunei. Tokyo’s push to enhance maritime security cooperation with Southeast Asian nations like Indonesia aligns with its broader goal of ensuring a rules-based order in the region. The donation of patrol boats and joint exercises with BAKAMLA are tangible expressions of this commitment, offering Indonesia both practical support and a diplomatic signal of solidarity.
Analysts suggest that Japan’s actions are also motivated by a desire to diversify its security partnerships beyond traditional allies like the US and Australia. “Tokyo is keenly aware that Southeast Asia is a critical theatre in the Indo-Pacific strategy,” said Dr. Lina Marwati, a maritime security expert at the University of Indonesia. “By equipping Indonesia with patrol capabilities and fostering joint exercises, Japan is building a network of partners capable of addressing shared challenges like piracy and territorial incursions.”
However, the partnership is not without complexities. While the patrol boat donation has been approved by Indonesia’s House Commission I, as confirmed by Commission Chair Utut Adianto of the Indonesian Democratic Party of Struggle (PDI-P), questions remain about the long-term implications of militarising vessels in waters close to disputed zones. If confirmed, the installation of weaponry on the boats could escalate tensions with other regional actors, though no official statement has yet detailed the nature of the planned armaments.
Historical Context and Regional Implications
Japan’s security assistance to Indonesia builds on decades of economic and diplomatic ties between the two nations. Since the early 2000s, Tokyo has positioned itself as a key partner in Southeast Asia’s maritime domain, with the JCG playing a pivotal role through regular deployments and training programmes. The 50th deployment of a JCG vessel to the region, marked by the Settsu’s arrival in Jakarta, highlights the consistency of this engagement at a time when piracy and illegal fishing remain persistent threats.
For Indonesia, the partnership with Japan offers a dual benefit: enhancing its capacity to patrol vast maritime borders—spanning over 17,000 islands—and reinforcing its strategic autonomy in a region often caught between competing superpowers. President Prabowo Subianto, who assumed office in October 2024, has prioritised modernising Indonesia’s defence capabilities, with maritime security emerging as a cornerstone of his administration’s agenda. The deployment of Japanese patrol boats to Nusantara waters aligns with this vision, particularly as the new capital’s location in East Kalimantan places it near key shipping lanes.
Yet, the collaboration also raises questions about Indonesia’s delicate balancing act in the South China Sea. While Jakarta has historically avoided taking sides in the dispute, its acceptance of security assistance from Japan—a vocal critic of China’s actions—could be interpreted as a subtle shift in posture. Some observers speculate that this move may prompt a response from Beijing, potentially in the form of increased naval activity near Indonesian waters. Such scenarios remain unconfirmed, and there is no evidence to suggest an immediate escalation, but the possibility underscores the high stakes of maritime diplomacy in the region.
Broader Regional Dynamics
The Japan-Indonesia partnership is emblematic of a broader trend in Southeast Asia, where nations are increasingly seeking external support to address security challenges without fully aligning with any single power. Countries like Vietnam and the Philippines have similarly received maritime assistance from Japan, including patrol vessels and training, as part of Tokyo’s efforts to build a coalition of like-minded states. These initiatives complement frameworks like the Quad—an alliance of Japan, the US, Australia, and India—while offering smaller nations resources to assert their maritime rights.
For Indonesia, the focus remains on safeguarding its Exclusive Economic Zone (EEZ), particularly around the Natuna Islands, where Chinese vessels have encroached in recent years. The addition of Japanese patrol boats to its naval fleet, though modest in scale, represents a step towards greater self-reliance. At the same time, joint exercises with the JCG provide valuable opportunities for knowledge exchange and interoperability, enhancing BAKAMLA’s capacity to tackle transnational threats like piracy—a persistent issue in the Strait of Malacca and surrounding waters. As Japan and Indonesia deepen their maritime cooperation, the establishment of a dedicated forum on maritime security promises to institutionalise dialogue on defence equipment and technology transfer. This could pave the way for further collaboration, potentially including joint production of maritime assets or advanced training programmes. Such developments, if realised, would mark a significant evolution in bilateral ties, moving beyond aid to a more equal partnership. However, challenges loom on the horizon. The integration of weaponry on the donated patrol boats, while intended to bolster security, may draw scrutiny from neighbouring states and complicate Indonesia’s non-aligned stance. Additionally, the sustainability of Japan’s OSA programme in the face of domestic budgetary constraints and competing regional priorities remains an open question. For now, both nations appear committed to navigating these uncertainties through sustained engagement.
In the broader context of Indo-Pacific geopolitics, the Japan-Indonesia partnership serves as a reminder of the intricate interplay between security, economics, and diplomacy. As tensions in the South China Sea persist, initiatives like the patrol boat donation and joint anti-piracy exercises offer a glimpse of how regional actors are adapting to an evolving strategic landscape. For Indonesia, the collaboration with Japan is not just about boats or exercises—it is about carving out a stronger role in shaping the future of maritime security in Southeast Asia.
