I've spent the last several weeks teaching my puppies how to swim. I've been taking them to the boat dock at a nearby lake. Most people don't know that all dogs don't know how to swim... as a matter of fact, most of them don't, and if you don't introduce them to the water properly, they'll be afraid of it. There are also some breeds that just can't swim.
So after several weeks, my girls have started swimming like fish. My little retriever, Neesa, has had her instincts kick in and she doesn't want to swim unless she has something to swim after... she's all about a purpose. My border/husky mix, Maia, is like a little ballerina in the water. She's learned how to make the water work for her and she just kind of floats/half swims around in circles... just casually enjoying the environment. Neesa tries to pounce on her in the water, and Maia just bobs right back up like a duck.
This last weekend I took them to an off-leash dog park that has a swimming lake. It was their first time swimming off-leash. After a couple hours you would think they would be tired, but on the long trek back to the car they were acting crazy and running everywhere. It was like the water energized them instead, but once we got in the car and started moving, they were just like toddlers... they knocked out all the way home.
They were content and calm all that evening and the entire next day.