The latest Taigei-class diesel-electric submarine, the Raigei, was launched on October 17, 2023, in Japan. The Raigei features upgrades to its power and operational management systems, making it the most powerful underwater hunter in the Japanese Maritime Self-Defense Force.

In mid-December 2023, Kawasaki Heavy Industries revealed its 2030 vision report, mentioning ongoing advanced submarine technology research projects with the Ministry of Defense. These technologies might be applied to new submarines following the Taigei-class. A significant focus is on incorporating long-range anti-ship and land-attack capabilities, with the installation of vertical launch systems for deploying long-range cruise missiles in the submarine's bow.

The recently launched Raigei is the fourth submarine of the Taigei-class, with a displacement exceeding 3000 tons, a length of 275 ft 7 in, a width of 29 ft 10 in, and a crew of 70 people. The construction cost is 70.2 billion yen or 470 million US dollars. The Taigei-class is one of the largest conventional submarines globally, with two in service, two launched, and two under construction. A total of eight are planned to replace the Oyashio-class.