Cerulean Lake, Alpine lake in Mount Assiniboine Provincial Park, Canada.

Cerulean Lake is a 25.7-hectare lake at about 2,220 metres in Mount Assiniboine Provincial Park, British Columbia, west of the Assiniboine Lodge and north of the Lake Magog campground. It measures roughly 900 metres long and 400 metres wide, lying west of the Continental Divide in the Southern Continental Ranges. Rainbow trout live in it, and exceptionally large specimens over 4.5 kg have been caught.

Mount Assiniboine Provincial Park was established in 1922 to protect these alpine lakes and surrounding landscapes as part of British Columbia's conservation efforts. This protected status has preserved the mountain environment and its natural features for over a century.

Cerulean Lake lies west of the Assiniboine Lodge and north of the Lake Magog campground, on the route between the lodge and the campground used by hikers and anglers. Rainbow trout and probably the rare cutthroat trout live in the lake, and fish over 4.5 kg have been caught there.

Cerulean Lake lies about 2,220 m up in Mount Assiniboine Provincial Park, west of Assiniboine Lodge and north of the Lake Magog campground. Day trips start from the lodge or the campground; the lake is roughly 900 m long and 400 m wide. Anglers have caught rainbow trout over 4.5 kg here, and the rare cutthroat trout may also be present.

The lake is part of a three-lake system with Sunburst and Magog Lakes, each offering a different vantage point of Mount Assiniboine's pyramidal peak. This arrangement allows visitors to experience the mountain from several distinct angles on a single trip.