Brittany Mahomes is proving she’s just as tough as her NFL star hubby … pushing through a fractured back to make sure she and her fam have fun on their Mexico vacation.

The 28-year-old was spotted hittin’ the beaches of Los Cabos on Thursday afternoon … looking no worse for wear despite dealing with a painful ailment.

Brittany — in a two-piece, green bikini — was seen building sandcastles with her 3-year-old daughter and another child … lugging around shovels and pales for the kiddos, ensuring they all enjoyed their day in the sun.

Britt — who revealed Wednesday she’s got a back injury that appeared to stem from her two pregnancies — seemed to be moving around OK … fluffing towels and playing with some water while getting dirty in the sand.

Then again, the mom of Sterling and Bronze might have had a little liquid help to manage it all — as she was seen with an orange-colored cocktail in her hand.

Patrick, of course, was there to provide assistance too … the Chiefs star was seen taking care of the tykes after they put a pause on their beach day.

Brittany had said after announcing her back issue this week that she was hopeful a vacay with the family would “make it better” … and so far, it seems so good!