It seems Asian people seldom sit or lie in the sun to get their skin tanned. That's not so common.
However, they do have a tradition to stand or sit in the sun in the very early morning about (6-6:30am) to get vitamin D from the sun. They believe the sun in the very early morning is good for health.
Also, doctors here advise that newborn babies should lie in the sun in the very early morning. Or else, their skin might get yellow.
Is it correct to say "I sunbathe in the early morning" in this situation?
However, "sunbathe" often makes people think about "getting brown"