If you’ve ever done open-water swimming for an extended period, you know it’s a challenge. Swimming in an ocean, lake or river, makes more demands on you than a pool. The elements can change on a whim, and that eventuality is frightening for some people.

If you’re training for an Ironman, or simply want to experience swimming in a less controlled environment, check out these destinations.

Seven Mile Beach – The Cayman Islands

Photo Credit: Marc Babin

This stretch of paradise on Grand Cayman is the place to get those laps in. The water is always crystal clear and gentle. Seven Mile Beach hosts the Flowers Sea Swim each year, where swimmers of all levels compete for top prizes.

Lake Tahoe – California/Nevada

Photo Credit: Tim Peterson

Lake Tahoe is one of the largest and deepest alpine lakes in North America. There are a few sporting events that happen here, including the Lake Tahoe Triathlon in August. The buoys and lifeguards will help keep you safe.

Loch Lomond – Scotland

Photo Credit: V2OSK

There are few destinations as dramatic as the Scottish Highlands. At Loch Lomond, open-water swimming is popular. When you’ve finished your swim, take a moment to enjoy the scenery. The craggy hills and woodlands are gorgeous.

Lake Wörthersee – Austria

Photo Credit: Adél Grőber

This is one of the most iconic lakes in Austria. It’s warm for an alpine lake. It reaches about 70 degrees in the summer. Aside from Ironman, check out the Wörthersee Swims. The most intense is the 34 KM Wörthersee Swim, which requires swimmers to be accompanied by a boat.