Lake Köyliönjärvi is located in the eastern half of the lake Pyhäjärvi area in the village Köyliö in Säkylä municipality and supports a wide range of fishing.
Lake Köyliöjärvi is about ten kilometres long and two kilometres wide at its widest point. It covers an area of approximately 12.5 km2. The lake is shallow: its maximum depth is about 13 metres and its average depth is about three metres. It is eutrophic due to nutrient loading in the lake. The lake’s water is usually cloudy and the visibility depth ranges from about 0.5 to about 1 metre.
Lake Köyliönjärvi is an interesting fishing area during whether frozen or not. The lake hides pike, perch, pike-perch and bream.
In the spring season, for example, large pike can be caught, but in summer, when the waters warm up, blue-green algae bloom and can make fishing difficult, but at the same time pike-perch can be caught on the surface. For anglers, there are abundant Cyprinidae and bream and tench. In winter, you can ice-fish for perch.
There are two sheltered resting places on the shores. Pappila’s lean-to is located at Pappilantie in the village of Kepola. Pispa’s lean-to is on Pispantie in the village of Vinnari, which also has mooring for boats.