The Oscar-nominated actress celebrated her 50th birthday with a trip to Cabo San Lucas ... beaming with tons of pride showing off her bikini bod. It's pretty clear Taraji's been hitting the gym. That much is clear based on her Instagram captions ... she hashtagged some of them like this -- #BAWDY, #hardasswork and #ImAddictedtotheworkout. Gains, baby.

Check out the pics ... it's easy to see why Taraji's more than happy to saunter in a tiny bikini while soaking up the sun south of the border. Gotta say ... 50 never looked so good. The "What Men Want" (you can say that again) star actually turned 50 on September 11 but is keeping the celebration going with a bunch of her girls ... coronavirus be dammed.