Tyrol has one of the highest waterquality in the world. This not only allows you to enjoy premium drinking water straight from the tap but also visit one of the many terrific lakes filled with it.
Cooling off in one of the many natural or artificial lakes is a popular pastime in Tyrol and can often be combined with a hike or bike ride. Some lakes further up the mountain, for example the Blaue Lacke, are far too cold to swim in (for any sane person at least) but still worth a visit as the view is just stunning.
You can find an overview of the most popular lakes in Tyrol here.
Most lakes are fairly cheap to enter or even free and usually offer an array of amenities like ice-cream parlours, restaurants and much more. Quite a few also offer fun activities like diving boards and towers, little artificial island or whole play-areas in and around the lake.

For those of you who prefer lakes close to Innsbruck we recommend taking a look here.
The list from blog.innsbruck.info features some of our favourites like the Natterer See which is also great for families. It is also very well situated to be combined with a hike which is ideal if you, like myself, are not the biggest fan of cold water and prefer to get your body temperature up before jumping in.
If you are on a budget we recommend the Baggersee (GER) in Innsbruck which free to enter after 6pm – just enough time for a few lanes and still dry off in the evening sun. Enjoy!