To expose one’s body to the sun in order to relax or to obtain a suntan.
A sunbathing session.
“Do you think it’s warm enough outside for a sunbathe?”
To bake in the sun.
A session of sunbathing.
sit or lie in the sun, especially to tan the skin
“I didn’t do much apart from swim, sunbathe, and sleep”
“on Kangaroo Island you’ll talk to wallabies and cuddle koalas, sunbake with seals on the pristine beach, and play with dolphins in the crystal clear waters”