Navigating the Divide: Why the U.S. Navy Must Resume FONOPs in Indonesia

Indications and Warnings Are Flashing Red

The Navy's operational "niceness" has not been reciprocated with flexibility. Instead, it has been met with a hardening, confident, and increasingly assertive stance from the Indonesian military (Tentara Nasional Indonesia, or TNI). Several recent events-some public, others quietly handled-should serve as a fleet-wide alarm bell:

• Incident 1: The Public Accusation (July 2023): Admiral Yudo Margono, a former commander of the TNI, testified before the Indonesian parliament that the United States was the biggest violator of Indonesian airspace. He wasn't whispering this in a private military channel; he was declaring it in an open political forum, citing eight U.S. military aircraft "violations" in the first half of that year alone. This public shaming was a clear signal. The core issue is that Indonesia contends these flights violated its sovereign airspace, while the United States largely views them as a legitimate exercise of international air navigation rights.
• Incident 2: The New Red Line (February 2025): Three U.S. Air Force C-130s transited from Darwin to Japan then back to Darwin that same day via the designated Archipelagic Sea Lane-3 (ASL-III). These flights were perfectly legal under any interpretation of international law, as reflected in the United Nations Convention on the Law of the Sea (UNLOS). Despite this, the Department of Defense (DOD) country team in Jakarta was informed that TNI headquarters staff (MABES-TNI) "should have been notified" before the flights took place. This is a dangerous and unprecedented claim. Indonesia is no longer just restricting where military vessels can transit, but if they can transit at all without prior consent-a clear violation of the "unobstructed" passage rights afforded by UNCLOS.
  

Figure 2: The Three Designated North-South Archipelagic Sea Lanes

Note: Indonesia's Government Regulation 37 of 2002 established three north-south sea lanes (ASL-I, II, and III). The U.S. C-130s in February 2025 used ASL-3 (right). The map's lack of any designated east-west route, such as through the Java Sea, is the central legal disagreement. | Source: Bureau of Oceans and International Environmental and Scientific Affairs, Limits in the Seas: Indonesia: Archipelagic and other Maritime Claims and Boundaries, no. 141 (Washington, DC: Department of State, 2014), 43-45, https://www.state.gov/wp-content/uploads/2020/02/LIS-141.pdf.

• Incident 3: The Coincidental Threat (April 2025): Coincidence is rare in this business. Just two months after the C-130 incident, the Indonesian Air Force (TNI-AU) conducted an internal exercise. The scenario involved three TNI-AU F-16 fighter aircraft launching a simulated intercept and forced grounding of a C-130 "violating Indonesian air space" operating out of ASL-3. This was a clear, unambiguous signal, dramatically increasing the risk of a tactical miscalculation between U.S. forces and the TNI.
• Incident 4: The Narrative Hardens (June 2025): During a multinational course on security cooperation hosted by the DOD in Honolulu, an Indonesian law professor publicly asked the lecturer why the United States "will sometimes violate the UNCLOS," referencing an alleged 2003 incident where aircraft from the USS Carl Vinson allegedly violated airspace over Bawean Island. (Note: This is known within the TNI as the "Bawean Incident," and was no small matter; it involved Indonesian F-16s intercepting U.S. F/A-18s, resulting in a dogfight, missile locks, and a formal diplomatic demarche from Jakarta. From the U.S. perspective, this was a textbook example of miscalculation; a diplomatic clearance request for the overflight had been submitted and approved by Jakarta, but this approval was never passed down to the local TNI-AU air controllers due to internal stovepipes.) While international law can be arcane to the general public, when "experts" and educators begin treating historical misunderstandings as fact, it signals a deeper entrenchment of the narrative that shapes Indonesia's future leaders and public opinion.

The "Grand Bargain" at the Heart of the Dispute

This entire disagreement stems from a central, hard-fought compromise at the heart of UNCLOS. Indonesia, as a nation of over 17,000 islands, effectively created the concept of the "archipelagic state." With its 1957 Djuanda Declaration, it boldly declared that all waters inside its baselines were not high seas, but sovereign internal waters.

For over two decades, the United States, the former Soviet Union, and other major maritime powers forcefully rejected this. It was seen as a radical attempt to close off vast swaths of the ocean, including critical routes like the Sunda Strait and Java Sea. The deadlock was finally broken during the Third UN Convention on the Law of the Sea (UNCLOS III). This was the "grand bargain": the United States and other powers, in a major concession, finally agreed to formally recognize the "archipelagic state" concept. In return, Indonesia and other new archipelagic states had to accept that these waters would not be "internal waters" but a new category: "archipelagic waters."

Critically, this new category came with a nonnegotiable right of ASL passage for all ships and aircraft. This right of passage, both through designated ASLs and "routes normally used for international navigation," was sacrosanct. It was the quid pro quo for recognizing the archipelagic state. When the United States challenges Indonesia's "creeping sovereignty" now, it is not simply arguing over a minor legal point; it is defending a central bargain of UNCLOS. Indonesia's attempts to impose notification requirements or restrict "normal routes" are a direct attempt to renege on that bargain, taking the concession of "sovereignty" while ignoring the "passage" obligation that came with it.

The Policy-Practice Disconnect

The U.S. legal position, articulated in State Department's Limits in the Seas No. 141, published in 2014, is clear:

• Partial Designation: Indonesia's designation of three north-south ASLs was accepted by the International Maritime Organization only as a "partial designation," since the government of Indonesia did not designate an east-west ASL.
• "Normal Routes" Apply: Under UNCLOS Article 53(12), if an archipelagic state "does not designate sea lanes" (i.e., east-west routes), the right of archipelagic sea lanes passage "may be exercised through the routes normally used for international navigation."
• S. Stance: Limits in the Seas No. 141 explicitly concludes that Indonesian attempts to restrict east-west routes (like the Java Sea) are "inconsistent with the navigational rights reflected in the LOS Convention."

This is U.S. policy, but U.S. practice tells a different story.

The last publicly documented freedom of navigation operation (FONOP) that directly challenged Indonesia's excessive maritime claims in the Java Sea was on May 12, 2017, conducted by USS John Paul Jones. Since then, U.S. Navy warships and aircraft have meticulously avoided the Java Sea and other non-designated routes, citing the desire to avoid unnecessary diplomatic strain.

This operational avoidance has been interpreted by Jakarta not as a gesture of goodwill, but as a tacit acceptance of their restrictive interpretation. U.S. policy is legally clear but operationally muddled, and that lack of clarity is now being capitalized on by TNI's de facto policy.

Figure 3: Indonesia's Archipelagic Baselines

Note: The solid crimson line defines the baseline from which Indonesia's 12 nautical mile (nm) territorial sea is measured. The waters inside this line, including the Java Sea, are claimed by Indonesia as sovereign "archipelagic waters." The United States legally challenges this, asserting the right of "archipelagic sea lanes passage" through these waters via normal routes, not just "innocent passage." | Source: Bureau of Oceans and International Environmental and Scientific Affairs, Limits in the Seas: Indonesia: Archipelagic and other Maritime Claims and Boundaries, no. 141 (Washington, DC: Department of State, 2014), 43-45, https://www.state.gov/wp-content/uploads/2020/02/LIS-141.pdf.