This dive site, Rausu, located on Japan's Shiretoko Peninsula, is renowned as the mecca for ice diving, offering one of the world's rarest opportunities to dive among drift ice. The ice originates from Russia’s Amur River, freezing and then carried by wind to Shiretoko from January to March. Divers explore this unique environment without explicit navigation structures, experiencing the dynamic, ever-changing seascape under the ice.
Despite the below-freezing water temperatures, the area teems with life. Divers can observe the fascinating shellless clam (Hadaka Kamegai or kurione) and its primary food source, the swimming clam (Mizin-Uki-Mai). Abundant crabs, shrimps, nudibranchs, and anemones add vibrant color to the icy landscape. Fish like the sea lamprey are also present, alongside the famous Rausu kelp, which creates unique underwater formations.
The best time to visit Rausu for ice diving is specifically from January to March when the drift ice arrives. This unique cold-water experience requires specialized dry suits and advanced cold-water diving skills. Divers should be prepared for below-freezing water temperatures and potentially moderate currents influencing the drift ice. While not suitable for typical snorkeling or freediving due to the extreme conditions, it offers a truly unforgettable experience for experienced cold-water divers.
