Nanatsugama Sea Cave Boat Tour

The Nanatsugama sea cave boat tour is a short sightseeing cruise departing hourly from Yobuko Port into a set of seven basalt sea caves carved into the Genkai Sea cliffs near Karatsu, Saga. Two vessels run the route: the standard Ikamaru cruise boat and the glass-hulled Zeela, which lets riders watch the water beneath the caves as the boat idles inside them. The tour requires no fitness or swimming ability and is suitable for all ages, including small children and travelers with limited mobility, since passengers remain seated throughout the 40-minute round trip; the main physical requirement is boarding the boat from the pier, where crew assist passengers across the gangway. Marine Pal Yobuko, the long-running operator based at Yobuko Port, provides the boats, licensed crew, and safety equipment; life jackets are available on board though not required to be worn while seated inside the cabin or open deck areas. Boats run year-round from around 9:30 to 16:30 (the Zeela's winter hours shift slightly earlier), but departures are suspended in high swell or strong wind, since the route runs close to the cave walls. The caves themselves were carved by wave action into the dark basalt columns of the Genkai coastline, and the boat noses into several of them so passengers can see the layered rock and hear the water echo off the walls. The calmest seas, and the clearest visibility for photography inside the caves, come April–June and September–November; midsummer can bring haze and choppier afternoon wind, and winter departures are more likely to be cancelled for rough water.