Sometimes it is okay just to relax and spend a day on the beach to catch some rays. The shores of Lake Oulujärvi are shallow and the sand is remarkably fine.
If you do not enjoy just sunbathing or if swimming is not enough exercise for you, there are also activities like beach volley or frisbee golf on some beaches.
The most popular beaches are situated at Manamansalo and Rokua. You can swim in the versatile Rokua Health & Spa Center around the year.