The Naruto Whirlpools are located on the strait between Naruto and Awaji Island formed by the shifting tides between the Pacific Ocean and the Inland Sea. This natural occurrence happens every 6 hours with the duration around 1 to 2 hours depending on the changing tides. Under normal circumstances, the whirlpools appear twice a day, once in the morning and another in the afternoon. Some whirlpools have a diameter of 20 meters, while unnoticeable swirls appear on calm days which can be viewed from different locations. Travelers are highly advised to check the whirlpool schedules on the official website to find out when the largest Naruto Whirlpools will form during the day. Time schedules vary depending on the weather and season of travel. Sightseeing cruises from the nearby piers of Tokushima Prefecture and Awaji Island are among the most popular way to view these whirlpools. Special double decker boats with underwater windows are available for guests to look into these natural wonders of Japan. While a stroll along the Uzu no Michi, which is a path underneath the Onaruto Bridge connecting Naruto city to Awaji Island, also offer a close look at these signature of Naruto through crystal clear glass. The Senjojiki Observatory within Naruto Park provides an overview look of the area along with the beautiful natural surroundings of Naruto city.