If you cannot swim, I implore you to learn.
From a fitness perspective. The only time I feel no pain, is when I'm afloat on my back, over my head in the water. The joints expand as the pressure releases, and muscles normally tense, let their guard down.
For mental health. As you near three hundred meters out, the sounds from shore start to fall off. Kids screaming on the beach, splashing in the water, music bumping in the cars, all of it. With your eyes closed it's a sensory deprivation tank.
Only red light makes it thru your eyelids, like a flashlight through your fingertips.
The water becomes the normal sensation across your skin, and you stop feeling it. When you bob up into the air, it feels like a sheet being rhythmically draped over your body, and lifted, as your center of mass drifts back into the cool below.
When you finally open your eyes, it's borderline hallucinatory. Your brain has become confused by long periods of monochrome light and decided there is too much red to see things as they really are. As a result you see the world in a blue-scaled, black-and-white. It's a little jarring the first time you look at a building you know has a red roof, against a background of what was once green foliage, and see a series of beautiful muted-blues.
But I've been "rolling a joint" for an hour now and people are starting to notice that I'm gone. Time to actually roll that joint and get back in the water.