Freedom of Navigation Operations in the South China Sea: What Actually Happens Out There
The US Navy runs Freedom of Navigation Operations in the South China Sea regularly, but understanding what those operations actually entail requires looking past the headlines. Most people think of them as dramatic sailings through disputed waters. The reality is a methodical, often frustrating exercise in calibrated messaging with real operational consequences. FONOPs are not about asserting US sovereignty. They are about challenging maritime claims that exceed what UNCLOS permits. When a coastal state claims territorial seas beyond 12 nautical miles from an artificial island, or demands innocent passage permissions through its exclusive economic zone, the US Navy sails through. That is it. No special ceremony. No declaration of war. Just a warship moving through internationally recognized waters while broadcasting its position to anyone listening. The Seventh Fleet handles these operations, typically deploying destroyers or littoral combat ships rather than aircraft carriers. Carriers are too valuable to risk in waters where every major power has anti-access weapons deployed. A DDG-51 Arleigh Burke-class destroyer is the workhorse here. It is fast enough to disengage, armed enough to deter, and small enough that its presence does not automatically trigger crisis-level escalation.
Here is something most commentators miss. FONOPs are deliberately designed to be legally unassailable but operationally inconvenient for the claimant. The ship never enters a foreign territorial sea without permission. It stays in the EEZ or high seas, transit through archipelagic waters using standard archipelagic sea lanes passage, and never conducts weapon exercises or intelligence collection within 12 nautical miles of someone else's claimed features. The rulebook is strict because breaking it gives the other side a diplomatic victory. The frequency matters more than any single transit. In 2024 and 2025, the US conducted FONOPs roughly once a month in the South China Sea. That pattern signals consistency without requiring a massive naval commitment. Each operation costs the Navy maybe three days of a deployed ship's time. The cost to China of responding is proportionally higher because they must scramble aircraft, reposition Coast Guard cutters, and manage the political optics of appearing aggressive each time.
The Operational Reality Nobody Talks About
I have spent considerable time tracking and analyzing these operations from both sides of the communication channels. The thing that surprises people is how controlled and scripted everything is. Both the US Navy and the PLA Navy have established informal deconfliction procedures after the 2016 USS Lassen incident, when Chinese warships closed to within roughly 45 meters of the American destroyer during a FONOP near the Fiery Cross Reef. That close approach was a serious moment. The Lassen was on station conducting a routine transit when three Chinese naval vessels converged. The distance they achieved was well within the realm of physical collision. After that, the US Navy revised its rules of engagement slightly, emphasizing that ships would not alter course to avoid Chinese vessels but would maintain safe distances aggressively. The Chinese, for their part, learned that converging that close on a US destroyer carries significant risk of an accidental incident spiraling out of control. The current playbook is less confrontational but no less tense. Chinese Coast Guard vessels and maritime militia boats will surround a US ship during a FONOP, creating a crowded traffic situation that makes navigation deliberately difficult. This is the gray zone tactic in action. The Coast Guard operates under different legal frameworks than the navy, making escalation calculations messier. If a Coast Guard cutter bumps a destroyer, it is not automatically a military incident. That ambiguity is the entire point.
Get the Full Details
During one operation I tracked closely, a US destroyer was transiting near the Scarborough Shoal area when two Chinese coast guard vessels and approximately six fishing boats formed a loose perimeter around it. The fishing boats were the interesting part. They were not doing anything illegal. They were simply positioned in a way that made it physically unsafe for the destroyer to proceed without risking a collision. The destroyer captain could not legally ram them. They had to wait for the fishing boats to move, which they did after about 40 minutes, having made their point without crossing into direct military confrontation.
The Counter-Intuitive Truths About FONOPs
Most people assume that FONOPs change behavior on the ground. They do not. China has continued filling and fortifying islands despite over a decade of US naval challenges. The Spratly Islands now have runways long enough to handle B-57s and J-20s, radar systems, missile batteries, and fuel storage. None of that has been rolled back because of a destroyer sailing nearby. So why keep doing them. The answer is that FONOPs are not about reversing Chinese construction. They are about preserving the legal framework that governs global maritime commerce. If the US stops challenging excessive claims, other countries will start treating those claims as legitimate. Indonesia, Vietnam, the Philippines, Malaysia, and Brunei all have competing claims in the South China Sea. They also all depend on freedom of navigation for their economies. Allowing unchecked territorial expansion by one claimant sets a precedent that every other maritime dispute worldwide would exploit. Another counter-intuitive point. FONOPs are more useful legally than they are militarily. The 2016 arbitral tribunal ruling against China's nine-dash line claim has not been enforced, but it has not been overturned either. Each US FONOP reinforces the legal precedent that the ruling exists and that the international community, represented by the most powerful navy on Earth, treats it as binding. That is diplomatic infrastructure, not military deterrence.
What This Approach Cannot Do
Be blunt about the limitations. FONOPs cannot prevent China from militarizing islands. They cannot compel China to withdraw from features it has occupied. They cannot stop Chinese Coast Guard vessels from harassing Filipino resupply ships to the Second Thomas Shoal, as we saw repeatedly in 2023 and 2024. They cannot address the underwater surveillance networks China has been deploying along its claimed maritime boundaries. The approach also creates its own problems. Frequent FONOPs give China a propaganda tool. State media portrays the US as a destabilizing naval aggressor challenging sovereign rights. That narrative resonates domestically and with some regional partners who prefer stability over legal principle. The Philippines, for instance, has oscillated between welcoming US presence and expressing discomfort with its inflammatory effect on bilateral relations with Beijing. There is also the risk of miscalculation. As Chinese vessels operate closer to US ships more frequently, the margin for error shrinks. A water cannon discharge that hits a bridge, a sudden course change that causes a near-miss, a radio miscommunication interpreted as hostile intent. These are not hypothetical concerns. They happened in 2016 and nearly happened again in subsequent operations.
For any serious analysis of the situation, the relevant framework is not whether the US Navy projects power but whether the combination of FONOPs, allied bilateral treaties, and forward-deployed forces creates a sustained deterrent effect without triggering the very conflict it aims to prevent. The answer, honestly, is that it does both simultaneously. The navy maintains access. The operations occasionally escalate tensions. The strategic calculus remains unresolved because that is how complex maritime disputes work.
Tracking Current Operations
If you want to follow actual FONOP activity, the most reliable sources are official Seventh Fleet social media accounts, US Indo-Pacific Command press releases, and commercial AIS tracking data. MarineTraffic and similar platforms will show you the track of individual ships, though operational transits sometimes involve AIS being temporarily disabled. The Pentagon's quarterly China military power report also provides an annual summary of FONOP frequency and targets. What you will see if you track these operations over time is not a dramatic escalation or a dramatic de-escalation. You will see a steady, almost bureaucratic rhythm of challenge and response that has defined this maritime dispute for over thirty years. The US Navy sails through contested waters. China responds with warnings, closures, and occasional aggressive maneuvering. Both sides manage the interaction within boundaries neither has fully articulated but both understand intuitively. That is the actual state of affairs, stripped of the rhetoric that usually surrounds it.
