A foreign submarine was detected passing by Amami-Oshima Island while submerged off Kagoshima Prefecture, the Defense Ministry said Saturday.
The ministry did not specify the vessel’s nationality but confirmed it was traveling westward through the island’s contiguous zone on Thursday afternoon.
The submarine did not violate Japan’s territorial waters and was determined to be west of Yokoate Island as of Saturday morning, it said.
In January 2018, Tokyo announced it had detected a Chinese nuclear-powered attack submarine near the Japan-administered Senkaku Islands. The uninhabited islands in the East China Sea are also claimed by Beijing, which calls them Diaoyu, and Taiwan, which calls them Tiaoyutai.
The event — the first time a Chinese sub had been observed in the Senkakus’ contiguous zone — triggered alarm in Tokyo, which then complained to Beijing.
The contiguous zone is a band of water beyond the 12 nautical mile territorial waters surrounding any national territory and extends out to 24 nautical miles.
