A Russian flotilla, which included frigates with hull numbers 333 and 343, sailed between Iriomote and Yonaguni islands in Okinawa prefecture on May 12 and 13, 2026. (Japan Joint Staff)
Ten Russian ships, including four naval vessels, sailed between Japan’s southwestern islands this week, an event a Joint Staff spokesman called “rare to see.”
The Japan Maritime Self-Defense Force spotted the Russian vessels at 11 p.m. Tuesday about 30 miles northwest of Iriomote Island, the Joint Staff said in a news release Wednesday.
The vessels included two Russian Steregushchiy-class frigates with hull numbers 333 and 343, a Dubna-class replenishment ship, a Bulk-class ocean-going tug and six cargo ships, according to the release.
Russian state-run news agency TASS identified hull number 333 as the RFS Sovershenny in a photo posted online May 14, 2020. The other frigate is the RFS Rezky, U.S. Naval Institute News reported Monday.
The vessels sailed southwest toward the Pacific Ocean through waters between Yonaguni Island and Iriomote over the next few hours, according to the release. The islands are part of Okinawa prefecture.
Foreign vessels are allowed to pass through the roughly 35-nautical-mile-wide waterway under international law, though Japan may respond if they enter its territorial waters, which extend 12 nautical miles from shore. The channel falls within Japan’s contiguous zone, which extends 24 nautical miles from its coastline.
The Japan navy’s JS Genkai, a Hiuchi-class auxiliary multipurpose support ship, surveilled the ships and gathered intelligence, according to the release.
The same vessels were spotted at 5 p.m. Saturday about 87 miles northeast of Tsushima island, according to a Joint Staff news release Monday. The vessels then sailed southwest between Tsushima and Kyushu, the southernmost of Japan’s main islands.
Tsushima is about 65 miles northwest of Kyushu.
Japan dispatched the fast attack craft JS Shirataka and a P-1 maritime patrol aircraft to monitor the passage, Monday’s release said.
This many Russian ships sailing together near Japan is a rare sight, the Joint Staff spokesman said by phone Thursday. The Joint Staff does not know why these vessels made the transits, he added.
The cargo ships do not belong to Russia’s navy but may have been chartered by the navy, he said. “Since we don’t know the exact arrangement, we’ve listed them as cargo ships,” he said.
Some Japanese government officials must speak to the media only on condition of anonymity.
The Sovershenny and Rezky on April 27 returned to Vladivostok, Russia, after a 12,000-nautical mile journey in the Pacific, which included port calls in Malaysia, Myanmar, India, Bangladesh, Cambodia and China, TASS reported that day.
On April 22, a Chinese guided-missile destroyer and frigate transited between Yonaguni and Iriomote, prompting Japan’s destroyer JS Akebono to monitor the situation, the Joint Staff said at the time.
