Chinas SDV sub exporting gray-zone warfare to the Gulf

China’s low-key rollout of an underwater commando craft in Saudi Arabia highlights how it is linking special operations warfare with a global arms-sales push.

This month, the South China Morning Post (SCMP) reported that China’s state-owned shipbuilder China State Shipbuilding Corporation (CSSC) unveiled a rare overseas glimpse of a secretive underwater combat vehicle at a major defense exhibition in Saudi Arabia, underscoring a push to market advanced naval systems to Middle Eastern buyers.

The model on display, designated SDV-01, is a surface-to-subsurface “swimmer delivery vehicle” designed to transport multiple frogmen for missions such as combat diving, underwater demolition and reconnaissance, according to the report.

Its appearance marked a rare public debut for a platform whose operational details remain scarce, with earlier public confirmation limited to a brief 2018 Chinese state television segment showing a similar vehicle being launched from a submarine or surface ship.

The SCMP report linked the capability to China’s evolving special operations doctrine for Taiwan and the South China Sea, citing recent large-scale drills and past exercises by elite naval units, while noting it remains unclear which variant the People’s Liberation Army Navy (PLAN) fields and whether the display model is operational.

Alongside the SDV-01, CSSC also showcased export-oriented amphibious and submarine models, underscoring a broader effort to present a more “systematic” naval export portfolio.

While official Chinese details remain limited, Naval News reported in November 2023 that the SDV-01 is a wet submersible designed to carry up to eight frogmen and their gear in an enclosed cabin with independent diver hatches and at least eight hours of air supply.

It measures 8.9 meters long, 1.5 meters in diameter, displaces no more than 4.5 tons, reaches up to 10 knots submerged, normally operates at depths of around 10 meters with a maximum of 40 meters and uses satellite, inertial and Doppler navigation with BeiDou and acoustic communications, with either manual or automatic control.

At the tactical level, the SDV-01 functions as a key enabler for clandestine maritime operations. Its utility lies in moving beneath surface surveillance during the brief interval between detection and engagement, enabling special operations teams to approach, insert or extract with reduced exposure to patrols and sensors.

Such platforms are designed less for decisive battles than for reconnaissance, sabotage, and targeting that create openings conventional forces can later exploit. That logic aligns with how Chinese special operations forces (SOF) are described in Western assessments.

John Chen and Joel Wuthnow wrote in a January 2022 China Maritime Studies Institute (CMSI) report that China’s SOF, including naval frogmen, are intended to play a preparatory role in a Taiwan seizure campaign by infiltrating ahead of the main landing force via special mission craft, submarines or helicopters to conduct reconnaissance, targeting, obstacle clearance and sabotage.

They explain that frogmen and other SOF would scout beaches and approaches, mark or clear obstacles, attack key targets such as ports, radar sites and command posts, guide precision strikes and conduct raids to disrupt defenders before and during the landing.

The same logic extends beyond Taiwan to the surrounding maritime geography. As outlined by Chad Machiela and other writers in an October 2025 Small Wars Journal article, PLA SOF could conduct rapid “micro-occupation” seizures of specific Philippine-held or claimed features to support a Taiwan campaign and expand control in the South China Sea.

Machiela and his co-authors argue that Mavulis Island could be seized within hours by PLA SOF to position sensors and missiles controlling the Bashi Channel, a critical chokepoint between the South China Sea and the Philippine Sea.

They add that heliborne or amphibious forces could take Itbayat and Batan (Basco) to create forward operating bases, and describe coercive takeover playbooks for Second Thomas Shoal, Scarborough Shoal and Sabina Shoal using maritime militia and follow-on forces to establish faits accomplis that secure flanks and chokepoints during a Taiwan contingency.

Beyond the South China Sea, similar anxieties shape Japan’s concerns over the Senkaku Islands. Reflecting those concerns, Kiyofumi Iwata mentions in a June 2025 SCMP article that China is laying the groundwork for a “landing and absorption” of the Senkaku Islands rather than merely posturing.

He argues that intensifying coast guard incursions, helicopter operations and expanding ship deployments point to preparations for an on-the-ground operation, with equipment upgrades and training focused on disembarkation missions.

A more gray-zone-focused scenario appears in Japanese policy analysis. Writing in June 2021 in the Japan Foreign Policy Forum, Watanabe Tsuneo argued that a Chinese takeover of the Senkaku Islands is most plausibly envisioned not as a conventional amphibious assault but as a gray-zone seizure by special forces or maritime militia to create a fait accompli.

Tsuneo warns that Chinese personnel could secretly land, raise the Chinese flag and refuse to withdraw, exploiting legal and response gaps to delay Japan’s Self-Defense Forces (JSDF) while consolidating control.

Placed against this backdrop, the appearance of the SDV-01 in Saudi Arabia looks less like a niche product pitch and more like the export of a particular way of war—one that emphasizes stealthy insertion, deniable presence and the creation of faits accomplis before an opponent can organize a response.

Maritime security in the Persian Gulf and Strait of Hormuz is fragile, with recent Iranian tanker seizures and missile drills around the region underscoring why Gulf states might consider enhanced littoral and special operations tools to protect critical shipping lanes.

It also fits a broader pattern of China using arms sales not only to generate revenue but to expand political influence and normalize its systems and concepts in foreign militaries.

China’s sales push in the Middle East builds on years of efforts to woo regional clients with a widening range of systems, often highlighting fewer political strings attached than those of Western suppliers.

In that context, unveiling advanced technology such as the SDV-01 in Saudi Arabia can be read as an attempt to court the kingdom by expanding the menu of available systems, exploiting frustration with US conditions and delays, and positioning China as an alternative supplier for states that face restrictions on access to Western armaments.

None of this means the SDV-01 is destined to become a centerpiece of Middle Eastern navies. The system remains opaque, its operational status uncertain and its performance untested in public view. But its appearance matters because it shows what China is choosing to showcase: not just big-ticket ships, but the tools of gray-zone competition and special operations.

If China is serious about turning platforms like the SDV-01 into export staples, it will also be exporting a style of warfare built around ambiguity, deniability and rapid faits accomplis rather than decisive set-piece battles—raising the risk that rivals in both Asia and the Middle East will seek to harden defenses against exactly the kind of quiet, incremental moves such systems are meant to enable.