Dwyane Wade & Gabby -- Biceps & Butt Cheeks ... For 1 Year Honeymoon

Dwyane Wade and Gabrielle Union celebrated their 1-year wedding anniversary this week ... by stripping down to their bathing suits ... and showing off their ridiculous physiques.

The two haven't revealed the location of their honeymoon trip -- but they seem to be having a good time ... splashing around in some pretty crystal blue ocean water.

It was just last year the couple tied the knot in a frickin CASTLE in Miami ... complete with tons of famous guests and music provided by John Legend, Ludacris and Questlove.

Congrats!