boats
In season, you can rent swan boats for paddling out on the lake Shikotse, there are also boats for rent on lake Toya.
Fishing
Is popular.
onsen
Being a volcanic lake, there are a number of hot springs in the vicinity. Both hot springs below also offer lodging. Noboribetsu is located here, and is one of most famous hot spring resort on Hokkaido, and Toyako Onsen is, as the name suggests, also packed with Onsens.