Yes they can swim and you can bath them too, but in a period of three months. So it would be like 3 times a year I do bath mine piggies sometimes more because they tend to get a bit smelly, but you should bath piggies just 3 times a year to avoid any skin irritation. Constant bathing can dry off their natural skin oil's leading to irritation. I have never heard or experience skin irritations, but you know its better to prevent.