Mid-depth circulation of the Shikoku Basin was measured by tracking four SOFAR floats drifting at the 1,500 m layer. Two floats were released on 17 April 1988 at 30•‹N, 135•‹59'E and tracked for 433 days. Another two were released on 3 November 1988 at 29•‹52'N and 133•‹25'E, and tracked for 234 days. Two 150 km in the western part of the basin.