Thai Navy Tours Chinese Shipyards: S26T Submarine 64% Complete, Delivery by 2028

Bangkok’s three-decade quest for an underwater fleet has inched forward again. A Thai naval delegation has spent the past ten days inside Chinese shipyards, classrooms and engine labs, seeking proof that the long-delayed S26T submarine will finally be ready before the end of the decade.

Snapshot of the visit

• Adm. Nares Wongtrakul led a team of senior officers to Wuhan and Shanghai between 9-19 December.

• China’s shipbuilder claims the first hull is 64 % complete and on track for sea trials in 2027.

• The controversial switch from a German MTU396 engine to Beijing’s CHD620V16H6 is now certified by Lloyd’s Register after 6,000-hour endurance tests.

• Bangkok has already paid 10 of 18 instalments; delivery is pencilled in for late 2028.

Why Bangkok cares about a submarine in Wuhan

Thailand has not operated a submarine since 1951, yet its maritime economy depends on trade routes that thread through the Strait of Malacca and the Gulf of Thailand. Planners in the Defence Ministry argue that an underwater deterrent would give the kingdom quiet intelligence-gathering capacity, help police illegal fishing and keep pace with neighbours—Vietnam, Indonesia, Malaysia and Singapore—that already field undersea fleets. Delay, they warn, could leave Thailand the odd man out in an era when ASEAN navies are modernising at speed.

From German MTU to Chinese CHD620 – the engine detour

The programme nearly collapsed in 2021 when export rules blocked the German-made MTU396 diesels promised in the original ₿13.5 B contract. After months of stalled talks, Bangkok accepted China’s indigenous CHD620 set in an amended September 2025 agreement. The new plant has now logged 6,000 hours on the bench, meets PLA Navy military standards, and—crucially for insurers—carries Lloyd’s Register classification. To sweeten the deal, Beijing offered ฿800 M in extra support, stretching the warranty from 2 to 8 years and throwing in additional simulators and spare parts.

What the Thai delegation saw inside the yard

At Wuchang Shipbuilding Industry Group the officers walked the length of an almost-finished pressure hull, inspected the quiet-running air-independent propulsion (AIP) module and watched weld inspections in real time. Project managers told the visitors that steelwork will close by mid-2026, internal fit-out by early-2027 and harbour trials before that year’s monsoon season. 64 % of overall work is certified complete; the yard claims to be three weeks ahead of the revised schedule, though Thai engineers still want vibration data once the engines are mounted.

Training the next generation of submariners

Hardware is only half the story. Across town at the Naval Engineering University, instructors showcased a submarine escape tower, navigation simulators, and damage-control mock-ups identical to the S26T’s layout. The Chinese side offered to take in Thai crews for English-language courses, AIP maintenance certificates, and tactical doctrine workshops, all pegged to internationally recognised curricula. Navy headquarters in Sattahip says the first class of 48 sailors could start as early as next April, giving Bangkok its first cadre of qualified submariners in over seventy years.

Strategic ripples across ASEAN waters

Analysts note that Thailand’s lone S26T will not tilt the regional balance overnight, but it does mark a symbolic step. The boat’s advertised Stirling AIP system should allow 20–30 days submerged endurance, enough to watch chokepoints or slip into the South China Sea if diplomacy ever demands. Supporters call it a cost-effective deterrent; critics still question spending in a shallow-water gulf and debate whether surface patrol ships might offer better return against threats like human trafficking or piracy. Either way, Bangkok’s move signals it will not sit out the quiet arms race unfolding beneath Southeast Asian waves.

Remaining questions – and the road to 2028

Budget watchdogs want clearer answers on life-cycle costs, transparency of future payments, and potential penalties if milestones slip again. The Navy counters that it has tied progress payments to independent inspection reports and can cancel the contract with compensation if China misses delivery by more than 18 months. For now, engineers are focused on the next hurdle—mounting and running the CHD620 inside the hull in the second quarter of 2026. If sea trials and crew training stay on course, Thailand could commission its first modern submarine just as the kingdom hosts ASEAN chairmanship in 2029, finally giving Bangkok a voice in undersea security dialogues it once watched from shore.

Fast facts in one glance

Price tag: about ฿13.5 B for hull, weapons and training.

Delivery window: Q4 2028, after a 40-month extension.

Engine: Chinese CHD620V16H6 diesel-electric with AIP module.

Construction status: 64 % complete, steelwork closing mid-2026.

Warranty: now 8 years, parts and simulators included.

Regional peers: Vietnam (6), Indonesia (5), Singapore (4), Malaysia (2) submarines in service.

Thailand’s last submarine: decommissioned 1951.

Next decision point: whether to fund boats 2 & 3 after evaluating S26T performance.