Nicole Murphy -- Board With Yoga ... Unless It's In A Bikini

Nicole Murphy and the chicks from "Hollywood Exes" found a way to make the Hawaiian coastline even more luscious ... with a very hot yoga session on the water.

The exes -- Nicole, Andrea Kelly, Sheree Fletcher, Mayte Garcia and new cast member Shanna Moakler -- traded yoga pants for bikinis ... balancing on all four in the water on paddleboards.