The Golden State Warriors got a bikini welcoming committee at a massive pool party in Vegas this weekend ... proving once again, it's good to be the champs.

Draymond Green, Matt Barnes and JaVale McGee hit up Encore Beach Club Friday ... boozin' on all kinds of alcohol from Don Julio 1942 to Hennessy to Jack Daniel's and Grey Goose -- while chilling in a private cabana.

The Dubs stars also downed a giant bottle of Perrier Jouet Rose as well, 'cause why the hell not?!

Wonder what the Cavs are doing?