Trace the tides on a cruise to see autumn’s great whirlpools

Use the tides and “◎” departures as a guide

Spring and autumn are peak seasons for whirlpools, when tidal currents are at their strongest. Autumn is described as a time when you can see some of the world’s largest whirlpools, reaching up to approximately 30 meters across, from close aboard a boat. A cruise through the strait on a clear autumn day, with a pleasant breeze, is another seasonal highlight. The size and shape of the whirlpools vary, and the conditions on the day—including the time and weather—affect what you’ll see.

The Naruto Strait’s whirlpools are formed by the tides in the Harima-nada Sea and the Kii Channel on either side of the strait. In this V-shaped channel, approximately 1.3 kilometers wide and 80–100 meters deep, high and low tides on the two sides occur alternately about six hours apart, creating a sea-level difference of up to approximately 1.5 meters. You can see how the complex currents create whirlpools while taking in the actual seascape.

Spring tides occur around the full and new moons, approximately every 15 days, when tidal movement is stronger. When planning, consider dates around a spring tide and choose a departure during the time of day when the currents are strongest. On the official website’s timetable, departures with the best chances of seeing whirlpools are marked “◎”. Calm seas and light winds are also favorable conditions; the website notes that strong winds can cause the whirlpools to disappear.

The currents in the Naruto Strait are among the fastest in the world. Along with the Strait of Messina and Seymour Narrows, it is counted among the “world’s three great tidal currents.” During spring tides, the water is said to flow at speeds exceeding 20 kilometers per hour. Knowing the power of the tides can help you notice not only the whirlpools but also the movement of the entire strait.

An approximately one-hour cruise aboard a tall ship, with onboard commentary

The cruise takes place aboard one of two tall ships, the Kanrin Maru or the Nippon Maru. An onboard guide joins every approximately one-hour cruise, sharing information about Awaji Island’s history and seasonal attractions as well as the views from the boat. Learning about the strait and the island adds another dimension to the time spent watching the whirlpools—a unique part of the onboard experience.

Check the official website for operating dates and departure times. The facility information lists opening hours as 9:00 a.m.–5:00 p.m. and says it is open year-round, but these details are separate from the cruise departure schedule. Before planning your visit, check the latest operating dates and timetable.

Fares are ¥3,000 for junior high school students and older, and ¥1,500 for elementary school students; both prices include tax. One infant per adult rides free. The boarding point is Uzushio Dome Nanairokan at Fukura Port. It is about a one-minute walk from the Fukura Highway Bus Terminal to the facility entrance.