The United States believed it understood the ocean better than anyone else during the most of the previous century. For a very long period, that assumption was true. Together, American research organizations, NOAA, and the Navy created a picture of the world’s underwater environment that was unmatched by any other nation. This picture was significant from a scientific, commercial, and military standpoint. Beijing had a major role in making that picture less complete than it once was.
The majority of China’s 64 oceanographic research vessels were constructed in the last 15 years. In terms of the number of ships, that fleet surpasses both NOAA’s own fleet and the entire American academic research fleet. The ships cover a large area. One ship, the Dong Fang Hong 3, carried out numerous survey missions in waters close to Taiwan, around Guam, and in portions of the Indian Ocean in just 2024 and 2025. It examined underwater object-detecting seabed sensor systems close to Japan in October 2024 and returned to the same coordinates in May 2025; this suggests recalibration or data retrieval rather than anything akin to an isolated scientific curiosity. Repeated over years on dozens of ships, the pattern is not subtle.
It’s not only the size of the fleet that makes this particularly important. It is the purpose of the data. Submarine operations are directly influenced by oceanographic knowledge, such as salinity layers, water temperature gradients, seabed topography, and how sound travels at various depths. Knowing where sound bends and where it doesn’t gives a navy a significant advantage over one that doesn’t. Because of China’s almost deliberate blurring of the boundaries between intelligence platforms and research vessels, civilian surveys and military data collecting are now practically synonymous. The scope of Chinese maritime science study has been described by American analysts at the Naval War College as “frankly astonishing.” That’s a methodical organization that uses remarkably straightforward language.
There is a real and measurable gap in ocean modeling. China implemented the LICOM K++ model in 2025, obtaining a horizontal resolution of one kilometer for simulations of the world’s oceans. Currently, the top-performing US models have a range of four to nine kilometers. Understanding how undersea environments change during extreme weather events, acoustic forecasting, and submarine navigation all depend on this distinction.
Microscale eddies and oceanic internal waves that US models presently have to theoretically approximate can be captured by China’s model. The disparity did not emerge suddenly; rather, it is the result of years of consistent, centrally focused investment in ocean science infrastructure, which the US was unable to match due to its more dispersed funding approach.
A surveillance component is added to the scientific picture by China’s “Underwater Great Wall,” a network of autonomous gliders, anchored buoys, and acoustic sensors positioned throughout the South China Sea and other vital waterways. Chinese and Russian forces connected their sensor networks and shared real-time acoustic tracking during joint drills with Russia in August 2025 in Vladivostok. This shows how data collection and operational use are already being integrated. Chinese official media reported that the stated objective was to leave submarines with nowhere to hide. That is not yet a fully developed capability, but it is an aim. However, the trajectory is evident.
The US hasn’t done nothing. Washington has taken steps to restrict technological transfers that could further advance Chinese capabilities, invested in new autonomous underwater vehicles through initiatives like Teledyne’s Sentinel Mission with Rutgers University, and fought to safeguard undersea internet cables. Once a fruitful avenue for exchanging data, US-China marine scientific collaboration has rapidly decoupled, with cooperative programs discreetly discontinued in recent years.
It is truly unclear whether it will be able to create domestic capacity quickly enough to close the deficit in the near future. In terms of overall naval reach and submarine capacity, the US still has significant advantages. However, America is no longer as dominant in the ocean as it once was, and it will take much more than a single administration’s budget cycle to close that gap.
