Hokkaido Blue Cave Cruise Halted due to Large Rockfall; Resumption of Tours Inside Deemed Difficult Due to Danger

The Yomiuri Shimbun

18:04 JST, July 20, 2025

SAPPORO — A large rockfall on Thursday afternoon has halted cruises inside the Blue Cave, a tourist attraction at a cliff in Otaru, Hokkaido, a council of cruise operators announced on Friday.

The Blue Cave, on the coast of the Shioya district in Otaru, opens to the sea through an entrance in a cliff. Small boat cruises in the cave have become a popular tourist attraction.

According to a person involved with the council of operators, there have been incidents of small rocks falling in the cave in recent years, requiring passengers to wear helmets during the cruise. This time, a rock measuring about 2 meters in diameter fell around the entrance to the cave. No one was injured by the rockfall, but the council of cruise operators deemed it too dangerous to enter the cave.

The Hokkaido government, which manages the coast, is urging people to be careful when traveling in the area by boat or personal watercraft.

Nobuo Mukai, a cruise boat operator and head of the council, said it will be difficult to resume boat access to the cave.

“The ‘Blue Cave cruise’ sign will have to be taken down to avoid misleading tourists,” he added.

Another operator said, “We’ll need to promote our cruises, as they still have appeal even without the cave.”