Is it normal to wear underwear under swim shorts?
Depends.It depends
It’s normal either way, but swim shorts with a built-in liner are usually worn without underwear. If you want extra coverage, choose swimwear made for swimming rather than everyday cotton underwear.
If your swim shorts have a mesh liner, you can usually skip underwear—that’s what the liner is for. Plenty of people do wear underwear underneath for comfort or coverage, though, so it’s not a big etiquette issue.
The main catch is that regular underwear can stay wet, feel heavy, or chafe. If your shorts don’t have a liner, swim briefs or other quick-drying underwear made for swimming are a more comfortable option.