第7回 屈斜路湖オープンウォータースイミング大会 ～（公財）日本水泳連盟認定OWS大会・サーキットシリーズ第11戦～

The Lake Kussharo Open Water Swimming Tournament is a Japan Swimming Federation-certified open water swimming event held on the shore of Lake Kussharo in Teshikaga, Hokkaido. The venue is set within Akan-Mashu National Park, giving the race a strongly natural character: swimmers compete in lake conditions where water temperature, depth, clarity, current, weather, and visibility are all part of the environment. The competition is conducted primarily under Japan Swimming Federation OWS rules, with local rules and the event’s own safety standards also applied. Participants swim freestyle over marked lake courses and must complete the designated route. The regulations specify permitted equipment such as swimsuits, goggles, limited swim caps, nose clips, and earplugs, while prohibiting items such as snorkels. Wetsuit use is controlled according to the applicable rules and water temperature, with stricter requirements for championship-related divisions. The event also emphasizes operational safety through athlete check-in, health questionnaires, equipment checks at call-up, timing band control, controlled entry and exit from the water, and restricted access to competition areas. The tournament includes categories for a wide range of swimmers, from younger participants to general entrants and registered competitive swimmers. It also includes championship and trial divisions connected to the broader open water swimming competition structure in Japan. Rather than being a pool-based event, it is organized around the demands of natural water: swimmers must understand the risks, have sufficient training and health, and follow staff instructions throughout the venue. The event combines competitive racing with a carefully managed open water setting on one of Hokkaido’s notable lakes.