The U.S. Office of Naval Intelligence projects that China’s submarine fleet will reach 70 boats by 2027, with three nuclear attack submarines, six guided-missile submarines, and two ballistic-missile submarines entering service inside three years. That assessment, delivered during congressional testimony earlier this year, signals a deliberate Chinese shift away from diesel-electric boats and toward a fleet built around nuclear propulsion, longer patrol ranges, and greater missile strike capacity. For U.S. Navy planners and allied navies operating in the western Pacific, the trajectory changes the math on undersea tracking, anti-submarine warfare, and deterrence.
What is verified so far
The strongest public evidence comes from the Office of Naval Intelligence commander’s testimony before the U.S.-China Economic and Security Review Commission in March 2026. In that appearance, later summarized by USNI News, the ONI chief stated that China is expanding its nuclear attack boat fleet and missile strike capabilities. The testimony laid out a specific construction breakdown: six SSGNs (nuclear-powered guided-missile submarines), three smaller-class SSNs (nuclear attack submarines), and two SSBNs (nuclear ballistic-missile submarines) are expected to join the People’s Liberation Army Navy in the near term. Together, those 11 nuclear-powered boats form the backbone of the projected growth to a 70-submarine force by roughly 2027.
That 70-boat projection and the three-class breakdown were subsequently cited in a May 2026 analysis published by Proceedings, which traced the figures directly to the ONI assessment and placed them in the context of China’s broader move toward nuclear-powered construction. The article underscored that the new SSGNs would likely be optimized for land-attack and anti-ship cruise missiles, magnifying the PLAN’s ability to threaten U.S. and allied bases and surface groups at longer ranges. It also stressed that the growing number of SSNs would give China more options for open-ocean patrols and blue-water presence missions beyond the first island chain.
The Department of Defense’s 2024 China Military Power Report provides additional context. A senior defense official, briefing reporters on that study, described ongoing Chinese naval modernization that includes submarine production as one of several priority lines of effort, alongside carrier aviation, long-range strike, and integrated air defenses. The Congressional Research Service has compiled these government assessments, along with data from the Defense Intelligence Agency, Jane’s, and other open-source references, into a running report for lawmakers on the implications of Chinese naval modernization for U.S. capabilities. Current fleet inventories tracked by the International Institute for Strategic Studies in its Military Balance 2025 edition place the PLAN submarine force near 60 hulls, with diesel-electric boats still making up the majority.
Those data points line up in one important respect: all of them depict a Chinese navy that is larger, more modern, and increasingly focused on nuclear propulsion than it was a decade ago. ONI’s testimony supplies the most granular numbers, Proceedings and CRS synthesize the trend lines, and Military Balance offers a snapshot of where the force stands today. Taken together, they provide a coherent-if still incomplete-picture of a fleet in transition.
What remains uncertain
Several gaps in the public record prevent a full accounting of how and when these submarines will actually reach operational status. No U.S. government source has published shipyard-level production timelines or material sourcing data that would confirm the three-year delivery window for all 11 boats. The six SSGNs represent the largest single category in the projection, yet the specific class designation, weapons fit, and construction site for each hull have not been detailed in publicly released testimony or in the unclassified portions of the China Military Power Report.
Exact current hull counts and retirement schedules for older Chinese submarine classes are also absent from the published record. Open-source estimates differ on how many aging diesel-electric boats remain in frontline service and how quickly they will be phased out. If China retires older boats at a faster rate than expected, the net fleet size could fall short of 70 even if new construction proceeds on schedule. Conversely, if retirements slow, the fleet could exceed that number. Neither the ONI testimony nor the Pentagon briefing addressed this variable in specific terms, leaving analysts to model a range of outcomes based on past Chinese practices and limited imagery.
Another uncertainty is operational readiness. Counting hulls does not reveal how many crews are fully trained, how often the submarines deploy, or how quietly they can operate. U.S. officials have not released public estimates of Chinese submarine availability rates or patrol days at sea. Without those metrics, it is difficult to translate the projected 70-boat inventory into a clear measure of day-to-day undersea presence in contested waters such as the Philippine Sea or the approaches to Guam.
No direct statements from Chinese officials or official PLAN documents confirm the 70-boat target or the specific three-class, 11-boat mix cited by ONI. The projection originates entirely from U.S. intelligence community analysis. That does not make it unreliable, but it does mean the figure reflects an external estimate rather than a declared Chinese plan. Beijing’s defense budgets and shipbuilding orders remain opaque enough that independent verification is difficult, and Chinese state media have offered only broad descriptions of “new-type” submarines entering service, without the detail needed to match them cleanly to Western designations.
How to read the evidence
The primary evidence here is the ONI commander’s sworn testimony before a congressionally chartered commission, as reported by naval correspondents who covered the hearing. That testimony carries institutional weight because ONI is the U.S. intelligence community’s designated authority on foreign naval forces, and the commission exists specifically to assess security dimensions of the U.S.-China relationship. The 70-boat figure and the construction breakdown are attributable to a named official speaking on the record in a formal setting, under oath, with prepared materials.
Secondary sources, including the Proceedings analysis and the CRS compilation, add interpretive value but draw from the same underlying intelligence. Readers should treat them as expert commentary on the ONI data rather than independent confirmation. The Military Balance 2025 from the International Institute for Strategic Studies offers a useful cross-check on current fleet size but does not independently project future construction, so it cannot validate the 70-boat number on its own.
The practical consequence of this evidence is straightforward. If the ONI projection holds, the PLAN will operate a submarine fleet that is not only larger but structurally different from the one it fields today. Nuclear-powered boats can stay at sea longer, patrol farther from home waters, and carry more advanced weapons than their diesel-electric counterparts. A fleet with a growing nuclear share would extend China’s ability to operate in the central Pacific, complicate U.S. carrier operations, and create more persistent undersea threats to bases and logistics hubs throughout the region.
At the same time, the uncertainties around construction timelines, retirements, and readiness argue for caution in treating the 70-boat figure as a fixed endpoint. For policymakers and the public, the most defensible reading is that China is clearly on a trajectory toward a larger, more nuclear-heavy submarine force, but the exact size, mix, and timing remain fluid. As new satellite imagery, budget data, and official statements emerge, they will either reinforce or revise the current ONI assessment. Until then, the available evidence supports a conclusion of significant undersea growth-without yet allowing a precise forecast of what the PLAN’s submarine fleet will look like on any specific date.
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*This article was researched with the help of AI, with human editors creating the final content.
