bathing cap
swimming cap

After the race, he pointed to the Norwegian flag on his swimming cap in reference to the 2011 Norway attacks.

Their heads, fitted with identical white swimming caps, incline toward each other, and their elbows stick up behind their heads.

I doff my swimming cap to the great Ian Thorpe.

Yeah you can but you've gotta use one of them cap things, not a swimming cap.

I held up the pink swimming cap.

A swimming cap?

The swimming cap had not turned gooey or become a liquid at all.

Eventually lighting flashes allowed them to see her red swimming cap.

Then I returned to my bit of beach and grabbed my stuff, hurrying back to the sunbed with the swimming cap.

Amanda ran and dived into the water without a swimming cap and stroked a good hundred yards.