The Port of Tomo is surrounded by a set of stone steps called gangi, which are used for mooring boats. The gangi in Tomonoura are the largest gangi made of stone in Japan at around 150 meters long with 24 steps.

According to records, the first set of these stone steps appear to have been built in the early Edo period (1603–1868), but around the 1950s they were buried in order to reclaim the land. The gangi that currently remain were built in 1811 and are still used by boats today.