Tidal differences exceeding 1.5 meters between the Pacific Ocean and Seto Inland Sea force water through the 1.3-kilometer-wide Naruto Strait at speeds up to 20 kilometers per hour, creating rotating vortexes up to 20 meters in diameter.
Spring tides around new and full moons produce the largest whirlpools. Daily tide schedules determine exact viewing times, as whirlpools only form during peak tidal flow periods and disappear during slack tide.
Yes. The whirlpools occur throughout the year, though their size and intensity vary with monthly tidal cycles and daily tide schedules.
Yes. Licensed operators use specialized vessels and maintain safe distances while navigating the strait. Tours adjust routes based on current tidal conditions.
The Uzunomichi walkway takes 30-45 minutes to explore. Boat tours last 20-30 minutes. Plan 2-3 hours total including travel between viewpoints and facilities.