Three Chinese maritime surveillance vessels entered Japanese territorial waters around the Senkaku Islands in the East China Sea on Friday morning, the Japan Coast Guard said.
The Haijian 23, 46 and 51 entered the waters between 9:50 a.m. and 10:10 a.m., according to the 11th Regional Coast Guard Headquarters in Naha, Okinawa Prefecture.
The vessels left Japanese waters by around 2:30 p.m. and continued to sail in the contiguous zone just outside the territorial boundary.
The Chinese fishery patrol vessels Yuzheng 201 and 202 were also spotted in the contiguous zone.
It was the 41st time that Chinese vessels have entered the territorial waters since the Japanese government purchased three of the five main islands in the group in September 2012.
The largest Chinese incursion in the waters occurred on April 23, when eight vessels were spotted entering.