Japan's Defense Ministry says three Chinese navy ships have traveled between Yonaguni and Iriomote islands in southwestern Japan.
It is the first time since April 2016 for Chinese navy ships to pass through the contiguous zone between the islands just outside Japan's territorial waters.
The ministry says the Maritime Self-Defense Force on Monday spotted three Chinese vessels, including two missile destroyers, sailing in the Pacific about 160 kilometers southeast of Okinawa Prefecture's Yonaguni Island.
The officials say the Chinese ships sailed between the islands on Tuesday.
They also say the MSDF confirmed the vessels later were traveling north in waters about 70 kilometers west of Uotsuri Island.
Uotsuri is one of the Senkaku Islands. Japan controls the islands. The Japanese government maintains the islands are an inherent part of Japan's territory. China and Taiwan claim them.
In December, the three ships traveled through the Osumi Strait off Kagoshima Prefecture. Several Chinese warships, including an aircraft carrier, conducted drills in the Pacific in the same month.