Japan Unveils Fifth Taigei-Class Submarine to Bolster Naval Power by 2031

Japan has expanded its underwater fleet with the commissioning of a new advanced submarine. The Taigei-class vessel, named JS Chōgei, entered service on March 10, 2026, as the fifth of its kind. This addition marks another step in Japan's plan to strengthen its naval capabilities with a total of twelve such submarines by 2031. JS Chōgei is now part of the 2nd Submarine Division under the 2nd Fleet, operating from Yokosuka Naval Base. The submarine measures 84 metres in length, displaces around 3,000 tons, and carries a crew of roughly 70 personnel. Its design includes improved stealth features and cutting-edge detection systems, setting it apart from earlier models.

The vessel is armed with Type 18 torpedoes and UGM-84L Harpoon Block II anti-ship missiles. Its advanced ZQQ-8 sonar suite and Kai-1 optronic masts enhance its ability to track and engage targets. Japan's next Taigei-class submarine, JS Sōgei, is already scheduled for commissioning in March 2027, with a tenth unit in the planning stages.

Meanwhile, Indonesia has finalised a $1.4 billion deal with Italy for six smaller DGK-class submarines. These 34-metre vessels, displacing 219 tons, are equipped with four torpedo tubes. The agreement reflects growing regional investment in underwater defence.

In a separate development, South Korea is pushing for legislative approval to begin its own nuclear-powered submarine programme. The move signals a broader trend of naval modernisation across Asia. JS Chōgei joins a fleet that has grown from one Taigei-class submarine in 2022 to five by 2026. Japan's long-term plan includes twelve of these advanced vessels by 2031, reinforcing its undersea defence posture. The submarine's deployment comes as neighbouring nations also expand their naval capabilities with new acquisitions and technology programmes.