The Aki-matsuri, or Autumn Festival, is the most energetic time of the year in Tomonoura. This annual three-day festival takes place from Friday to Sunday in mid-September at Watasu-jinja Shrine, part of Nunakuma-jinja Shrine. The spirit enshrined there, Ōwatatsumi-no-mikoto, is a sea kami of maritime safety who has watched over the people of the port town of Tomonoura since long ago.

The seven neighborhoods that once made up Tomonoura take turns hosting this festival. On the first day of the festival, the kami is transferred from Watasu-jinja Shrine to the neighborhood in charge of the festival that year. On the second day, the host neighborhood serves as the resting point, or “otabisho,” for the kami. On the third day, the kami returns to the shrine in an event known as “Kangyo-sai.” In preparation for celebrating these events, houses in the host neighborhood are adorned with paper lanterns and other festive decorations.

Following the kami’s return to the shrine, the climax of the festival is when a float called “chōsai” is paraded around Tomonoura. This festive three-day event expresses the energy and enthusiasm of the people of this port town.