The Naruto Whirlpools are a spectacular natural phenomenon that occurs in the Naruto Strait, between Naruto City in Tokushima Prefecture and Minami-Awaji City in Hyogo Prefecture. Formed by powerful tidal currents, these enormous swirling waters are among the largest whirlpools in the world. During periods of especially strong spring tides, individual whirlpools can reportedly reach up to 30 meters in diameter, creating an extraordinary sight for visitors.
The Naruto Strait is a narrow passage, approximately 1.3 kilometers wide, connecting the Pacific Ocean with the Seto Inland Sea between Honshu and Shikoku. The whirlpools form as enormous volumes of seawater move between the two bodies of water in response to the tides. Water flows into the Seto Inland Sea twice a day and flows back toward the Pacific Ocean twice a day, creating powerful currents as the tide changes approximately every six hours.
The difference in water levels between the Seto Inland Sea and the Pacific Ocean can reach approximately 1.5 meters. Combined with the narrow strait and its complex underwater terrain, this difference produces tidal currents traveling at around 13 to 15 kilometers per hour. During spring tides, the current can reach approximately 20 kilometers per hour, making it one of the fastest tidal currents in Japan.
The Naruto Strait is sometimes included among the world’s three great tidal-current areas, alongside the Strait of Messina in Italy and Seymour Narrows in Canada. Its dramatic currents are a major reason why the whirlpools have become one of the region’s most famous natural attractions.
Whirlpools form where the fast-moving central current meets slower-moving water near the shores of the strait. The resulting differences in speed and direction create rotating currents. Several whirlpools may appear simultaneously, forming and separating as they move through the channel. Both clockwise and counterclockwise rotations can occur.
The whirlpools are particularly impressive during the spring and autumn spring tides. Under favorable conditions, they can reach diameters of 10 to 20 meters, and observations have recorded depths of more than 20 meters. Their size and intensity vary according to tidal conditions, so the spectacle changes throughout the day.
One of the most exciting ways to experience the Naruto Whirlpools is from a sightseeing boat. Cruises take visitors close to the turbulent water, allowing them to observe the swirling currents from sea level. The view can be particularly dramatic when large whirlpools form nearby, revealing the tremendous force of the tides.
Another popular viewing location is Uzu-no-Michi, a sightseeing facility built beneath the Onaruto Bridge. Its enclosed walkway extends above the Naruto Strait, approximately 45 meters above the sea. Glass-floor viewing areas allow visitors to look directly down at the water and watch the currents swirling beneath their feet.
Because the whirlpools depend on tidal conditions, their size and visibility change over time. Checking the tide schedule before visiting can help you choose a period when the currents are expected to be strongest.
For safety reasons, stopping or parking on the shoulder of the Kobe-Awaji-Naruto Expressway while crossing the bridge is prohibited. Vehicles must continue moving in accordance with the road’s traffic regulations.
Various initiatives have explored the possibility of securing World Natural Heritage recognition for the Naruto Whirlpools. In October 2012, the three municipalities on Awaji Island established the Council for Promoting the World Natural Heritage Registration of the Naruto Whirlpools. In September 2013, Minami-Awaji City and Naruto City formed another organization to promote international recognition of the whirlpools and strengthen cooperation across the strait.
Proposals have also considered the possibility of collaborating with regions in Norway and Scotland, in the United Kingdom, where similarly remarkable tidal-current phenomena occur. These efforts reflect the area’s commitment to protecting and sharing the whirlpools’ natural and scientific value.
The dramatic waters of the Naruto Strait have inspired artists and photographers for generations. One notable example is the ukiyo-e woodblock print Awa Province: Whirlpools and Waves at Naruto, part of Utagawa Hiroshige’s series Famous Views of More Than Sixty Provinces. The artwork vividly captures the swirling waters and crashing waves, preserving the power and beauty of this natural spectacle through traditional Japanese art.
The Naruto Whirlpools offer a remarkable opportunity to witness the power of the natural world. Created by the meeting of powerful tidal currents, these constantly changing formations can be admired from sightseeing boats, observation facilities, and viewpoints beneath the Onaruto Bridge. Whether you are fascinated by natural science, photography, or spectacular coastal scenery, the whirlpools provide an unforgettable experience on the border between Hyogo and Tokushima prefectures.