The nuclear-powered aircraft carrier USS Abraham Lincoln made a port call Friday at Sasebo, Nagasaki Prefecture.
The 102,000-ton Nimitz-class flattop, with about 5,350 crew members aboard, is en route to operations in the Middle East, according to U.S. Navy officials.
The stopover is part of worldwide operations and to underscore the U.S. presence in East Asia, the officials said.
The last time a nuclear-powered U.S. aircraft carrier made a port call in Japan was in September 1997, when the Nimitz stopped over in Yokosuka, Kanagawa Prefecture.
The Abraham Lincoln, which is docking in Japan for the first time, plans to leave Sasebo on Monday morning after taking on provisions and allowing its crew to rest.
Since the Sept. 11 terrorist attacks on the United States, Maritime Self-Defense Force ships have escorted some U.S. warships entering or leaving Japanese ports. But Friday, the MSDF "did not guard the carrier at sea," an MSDF official said.
More than 10 patrol boats from the Japan Coast Guard, which is a civilian government entity and not part of the MSDF, accompanied the Abraham Lincoln as it arrived in Sasebo.
Antinuclear protesters aboard 18 fishing boats tried to approach the arriving vessel, but the coast guard blocked their path.
The protesters believe a port call by an atomic-powered vessel goes against Japan's three nonnuclear principles of not producing, possessing or allowing nuclear weapons on its territory.
Another group of about 200 activists gathered on a hill overlooking the port, holding antinuclear banners and voicing protests.