WEBAs of 2019, Japan's territory is 377,975.24 km 2 (145,937.06 sq mi). [1] Japan has the sixth-longest coastline in the world at 29,751 km (18,486 mi). Because of its far-flung outlying islands, Japan has the eighth-largest exclusive economic zone in the world, covering 4,470,000 km 2 (1,730,000 sq mi).