Justina Valentine Fire-Hot Snaps to Celebrate Her 39th Birthday

Justina Valentine is 39 and looking great ... and if you need receipts, this gallery’s got 'em!

The birthday babe knows exactly how to crank up the heat -- and it’s not just the signature red hair, 'cause those barely-there bikinis are doing all the talking and showing off every curve.

Justina’s body confidence is on full blast, keeping it on-brand in fiery red ... no matter what corner of the globe she’s posing in.