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Maritime Jurisdiction· 4 min read· in Defense & Security

How a Routine Indonesian Naval Transit East of Taiwan Became a Geopolitical Flashpoint

A brief passing exercise between an Indonesian frigate and a Chinese warship east of Taiwan has triggered diplomatic protests and competing narratives over maritime jurisdiction.

By Layla Zaher

When the Chinese and Indonesian navies conducted a joint exercise east of Taiwan in mid-August 2026, initial reactions framed the event as a dramatic military alignment between Beijing and Jakarta. The optics of Southeast Asia's largest economy conducting unprecedented naval drills with the People's Liberation Army (PLA) in highly contested waters suggested a major shift in regional security architecture.[1][7]

The reality of the operation is considerably more nuanced. Rather than a complex combat simulation or a formal mutual defense pact, the interaction was a "passing exercise"—or PASSEX—a standard maritime protocol conducted when warships transit near one another.[4][5]

The Indonesian frigate KRI I Gusti Ngurah Rai was simply returning home from a joint exercise with the Russian Navy in Vladivostok. As it navigated the Philippine Sea and the Pacific Ocean east of Taiwan, it engaged in routine communications and formation maneuvers with the PLA Navy's Type 054A frigate Honghe.[1][5]

Yet in the highly calibrated environment of the Indo-Pacific, even routine maritime diplomacy carries profound strategic weight. The location of the exercise—within Taiwan's exclusive economic zone (EEZ)—transformed a standard naval courtesy into a geopolitical flashpoint, triggering immediate condemnation from Taipei and highlighting Beijing's evolving strategy for asserting jurisdiction.[3][6]

A passing exercise (PASSEX) is a standard naval protocol for communication and maneuvering.

To understand the friction, one must examine the geography. The waters east of Taiwan face the Pacific Ocean and the Philippine Sea, serving as a critical buffer zone and transit corridor. Historically, China's military pressure on Taiwan has concentrated on the Taiwan Strait to the west.[7]

However, Beijing has systematically expanded its presence off Taiwan's eastern coast. In June 2026, China initiated coast guard patrols in these waters, a move designed to normalize its administrative control and project power beyond the first island chain.[1][6]

The PLA's Eastern Theater Command capitalized on the Indonesian frigate's transit to reinforce this narrative. By publicly announcing the exercise in advance and framing it as a joint effort to "safeguard regional peace and stability," Beijing effectively used Jakarta's participation to validate its operational presence in the area.[1][2]

Chinese military analysts explicitly described the drill as a demonstration of China's sovereign rights and jurisdiction over the EEZ east of Taiwan. Inviting a foreign navy to conduct training in these waters, they argued, normalizes China's administrative authority and expands its "toolbox" for maritime rights protection.[2]

Taiwan's response was swift and unequivocal. The Mainland Affairs Council in Taipei labeled the exercise a "military provocation," accusing Beijing of political manipulation. Taiwanese officials argued that China was attempting to create a false impression before the international community that it holds jurisdiction over the waters east of the island.[6]

The exercise took place in the Philippine Sea, within Taiwan's Exclusive Economic Zone.

Geointelligence analysis confirmed that the exercise took place between 6:30 a.m. and 9:30 a.m. on August 12, inside Taiwan's EEZ. Tracking data showed the Indonesian frigate making a tight loop to align with the Chinese vessel before proceeding south, passing close to Taiwan's contiguous zone without entering it.[3]

For Indonesia, the incident underscores the complexities of maintaining a "free and active" foreign policy in an era of great power competition. Jakarta has consistently sought to balance its economic ties with China against its security partnerships with the United States and its allies.[5]

The Indonesian Navy quickly moved to de-escalate the narrative, emphasizing that passing exercises are a universal naval tradition and a manifestation of maritime diplomacy, not an endorsement of territorial claims. A spokesperson clarified that the KRI I Gusti Ngurah Rai was scheduled to conduct similar exercises with other nations, including Japan and the U.S. Seventh Fleet, along its route.[4][5]

Despite these clarifications, the exercise highlights a broader trend: the increasing militarization of the Philippine Sea. As Washington and its allies tighten defense cooperation—evidenced by recent maritime delimitation talks between Japan and the Philippines—Beijing is actively seeking to demonstrate its own network of security partnerships.[1][7]

Naval officers coordinate maneuvers and communications during a routine transit.

The diplomatic fallout also reveals the asymmetric nature of maritime signaling. While Indonesia viewed the PASSEX as a low-stakes diplomatic courtesy, China leveraged the interaction to achieve specific strategic messaging goals regarding Taiwan.[2][4]

This dynamic places middle powers like Indonesia in a delicate position. Routine military engagements can be easily co-opted by larger powers to advance territorial claims, requiring smaller nations to carefully calibrate their operational transparency and public messaging.[4][5]

Ultimately, the mid-August exercise serves as a node in a larger infrastructure of regional tension. It demonstrates how standard naval protocols are increasingly weaponized in the gray zone of maritime competition, where the narrative surrounding an operation is often as consequential as the operation itself.[1][3][6]

Key points

  • Chinese and Indonesian naval vessels conducted an exercise east of Taiwan in mid-August 2026.
  • Beijing framed the event as a joint drill demonstrating its jurisdiction over the area.
  • Indonesia clarified it was a routine passing exercise (PASSEX) during a homeward voyage from Russia.
  • Taiwan condemned the interaction as a military provocation and an exercise in political manipulation.

What we don’t know

  • Whether the Indonesian Navy will alter its future transit routes to avoid contested waters east of Taiwan.
  • How the United States and its regional allies will adjust their own naval patrols in response to China's expanded presence.
  • If Beijing plans to regularize joint exercises with other non-aligned nations in the Philippine Sea.

How we got here

  1. June 2026

    China initiates coast guard patrols in the waters off Taiwan's eastern coast, expanding its maritime presence.

  2. July 29, 2026

    The Philippines submits an official maritime map to the UN, prompting increased regional focus on maritime delimitation.

  3. August 11, 2026

    China's Ministry of National Defense publicly announces a planned joint navigation exercise with Indonesia east of Taiwan.

  4. August 12, 2026

    The Indonesian frigate KRI I Gusti Ngurah Rai and Chinese frigate Honghe conduct a passing exercise between 6:30 a.m. and 9:30 a.m.

  5. August 12, 2026

    Taiwan's Mainland Affairs Council condemns the exercise as a military provocation and political manipulation.

Chinese State Security Apparatus 35%Taiwanese Defense Establishment 35%Indonesian Non-Aligned Establishment 30%
Chinese State Security Apparatus
Argues that the exercise validates China's jurisdiction over the waters east of Taiwan and demonstrates growing security cooperation with Southeast Asian nations.
Taiwanese Defense Establishment
Views the drill as a dangerous gray-zone escalation and a deliberate attempt to falsely project Chinese administrative control to the international community.
Indonesian Non-Aligned Establishment
Insists the interaction was a routine, apolitical passing exercise consistent with standard maritime diplomacy and international naval protocols.

Perspectives this story doesn't cover

  • U.S. Indo-Pacific Command
  • Philippine Maritime Security Forces
  • Commercial Shipping Operators in the Philippine Sea

Sources

Source coverage

7 outlets

3 viewpoints surfaced

Chinese State Security Apparatus 35%Taiwanese Defense Establishment 35%Indonesian Non-Aligned Establishment 30%
  1. [1]South China Morning PostChinese State Security Apparatus

    PLA holds first joint naval drill with Indonesia in waters east of Taiwan

    Read on South China Morning Post →
  2. [2]Global TimesChinese State Security Apparatus

    China, Indonesia to hold exercise east of Taiwan island in mid-August, first such drill carries 'great significance'

    Read on Global Times →
  3. [3]Domino TheoryTaiwanese Defense Establishment

    China's Naval Exercise With Indonesia Took Place in Taiwan's Exclusive Economic Zone

    Read on Domino Theory →
  4. [4]AsiaOneIndonesian Non-Aligned Establishment

    Indonesia says navy drill with China that angered Taiwan was routine

    Read on AsiaOne →
  5. [5]Antara NewsIndonesian Non-Aligned Establishment

    Indonesia explains naval exercise with China near Taiwan

    Read on Antara News →
  6. [6]The Japan TimesTaiwanese Defense Establishment

    Taiwan condemns 'dangerous' planned Chinese navy drills with an Indonesian warship

    Read on The Japan Times →
  7. [7]TempoIndonesian Non-Aligned Establishment

    China, Indonesia Plan Joint Exercise East of Taiwan

    Read on Tempo →

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