: Players use specific layered clothing or patterns that mimic the look of a bikini tan.
: In the "Arrange" menu, set your suntan oil to the lowest setting initially, then increase it while wearing the desired outfit to "bake" the lines in.
Tan lines were introduced with the Island Living expansion pack.
: Click on a lounge chair or towel and select "Sunbathe".
: The lines your Sim develops will match the exact shape of the swimsuit they are wearing at the time.