Retirement looks REALLY good on Tom Brady ... 'cause the 7-time Super Bowl champ ditched his top during his yacht getaway in Greece -- and the dude looks pretty shredded!!
TB12 and his kids have been living it up on the luxurious "Madsummer" boat this week ... enjoying all kinds of watersports as they soak in some vitamin D.
But it hasn't just been Ben, Jack and Vivian testing out their skills in the water -- the 45-year-old daddy even showed them he's still down to partake in the fun and games .