The new boat, JS Taigei (pennant number SS 513), was enrolled into the Escort Division 4 of Escort Flotilla 2, which is based at the Yokosuka naval base in Kanagawa Prefecture shortly after being handed over by shipbuilder Mitsubishi Heavy Industries (MHI) at its facility in Kobe City.

According to the JMSDF, the new submarine has a crew complement of about 70, an overall length of 84 m, a beam of 9.1 m, a draught of 10.4 m, and a standard displacement of about 3,000 tonnes, making it is slightly larger than the well-known previous Soryu-class SSKs, which are 84 m long, 9.1 m wide, 10.3 m depth, and have a standard displacement of 2,950 tonnes.

Taigei means “big whale” in Japanese and was borne by a submarine tender in the Imperial Japanese Navy. The new submarine, which cost about 80 billion yen ($690 million) to build, is powered by a diesel-electric engine generating 6,000 hp.

According to the JMSDF, the new boat has lithium-ion batteries instead of lead-acid batteries, just like the final two Soryu-class boats for the JMSDF, Oryu (SS 511) Toryu 512), which were commissioned in March 2020 and began service in March 2021, respectively.

The Taigei class will use the same torpedo counter-measures system that has been used on the last four Soryu-class ships. It is expected to use Japan's newest torpedo, the Type 18, which is expected to replace the Type 89. The new torpedo, first known as the "G-RX6," will enhance several areas, including propulsion, target detection, and processing.

The UGM-84L Harpoon Block II anti-ship missile can also be used against surface targets by the class. This missile has a range of 248 kilometres, which is sufficient for Japan to obtain "enemy base attack capabilities," which is still being debated in Tokyo.

The second Taigei-class submarine, Hakugei (pennant number SS 514), was launched in October 2021 by Kawasaki Heavy Industries (KHI) and is scheduled to enter service in March 2023. In Japanese, Hakugei means "white whale."

The Ministry of Defense has allotted funds for the construction of four more submarines of the class – SS 515, SS 516, SS 517, and SS 518 – with MHI building the first, third, and fifth, and Kawasaki Heavy Industries (KHI) building the second, fourth, and sixth.

Most recently, on December 24, 2021, the Japanese defence ministry was allocated 73.6 billion yen for 2022 starting April to build the sixth boat of the class.

So far, Japan is the only country known to have fitted lithium-ion batteries into SSKs, with South Korea expected to be the following country to do so.