Whether you are a mermaid, scuba diver, swimmer or whatever - the Waterbaby system will make use of the amazing LBOM (LustBaby Outfit Manager) System and the RLV functions in your favorite alternate SL Viewer (like Greenlife Emerald Viewer) to automatically change you whenever you go into Linden Water!
https://www.xstreetsl.com/modules.php?name=Marketplace&file=item&ItemID=1656143
Bear in mind that this takes a bit of setup and all that - but once you get it rockin' in rollin - it is very very cool.