It makes sense though. In the (which Legend of Korra is assumed to be set in) the first real swimsuits were made. In Avatar the Last Airbender they didn't have a defined swimwear so they wore whatever.
NARUTO - Sasuke wants to be Hokage. Yeah and ill spread wings fly to Japan and shake kishimotos hand personally for this troll action. Biggest Facepalm ever. All jokes aside predicted this would happen (Oh my LOL)