Lake Kuolimo has very clear and pure waters. In fact, the water is so pure that when swimming in it, one could almost believe they are bathing in drinking water!
Lake Kuolimo was created about 4 000 years ago as the result of a contusion of bedrock. A groove was created as a result of such a contusion, along which a powerful ice river owed towards an area in which the rock was soft. The ice river eventually formed a lake in the area.
The western beaches of the lake are made of granite, but the rest of the area is mainly rapakivi granite. In statistics concerning the area of Finnish lakes, Kuolimo is ranked 56th. Ridges pass through the lake, forming narrow peninsulas, sand banks, sandy beaches and islands. Lake Kuolimo is bounded in the south by 2. Salpausselkä ridge.
Lake Kuolimo is the heart of the community. It is rich and special. The area is geologically and biologically an exceptionally diverse combination of ridges, cliffs, mires and barren lakes. In addition, relics of the ice age, the char and sculpin, live in the lake. Lake Kuolimo is, in addition to the western part of Lake Saimaa, probably the only breeding area for Arctic char in the whole of the Vuoksi River waterway.
Lake Kuolimo ows into Lake Saimaa along two routes, via Partakoski and Kärnäkoski, both of which have impressive rapids. Partakoski is additionally the only spawning place for lake trout in the region of southern Saimaa. A canoe can pass from Lake Kuolimo to Lake Saimaa at the Orraintaipale former crossing point, at which the carrying distance is about 300 meters.
The area of Lake Kuolimo has a large number of leisure-time residences relative to the population of the municipalities. The lake is also considered to be one of the cleanest in Finland. The largest islands in the lake are Lehtisensalo (311 ha), Suomensalo (178 ha), Lamposaari (126 ha) and Paassalo (120 ha). Association Pro Kuolimo ry functions in the protection of the lake.
Some interesting sites that can be accessed on a boat or a canoe include Lehtisensaari and Suomensalo islands, Lepänkanto beach and recreational area, and Luotolahti shelter.
There are marked boat routes to Lake Kuolimo. The boating passage map was remade in 2010. Fishing licenses can be purchased from Etelä-Karjalan kalatalouskeskus (”South Karelia Fishery Centre”).