Patrick Mahomes’ wife, Brittany, really is a bikini model now — the Sports Illustrated Swimsuit rookie put her stunning body on display during her vacation in Mexico … and flaunted some serious underboob in the process.

The Kansas City Chiefs superstar and his longtime partner had a romantic trip in Cabo San Lucas over the past several days … but on Sunday, it was all about the girls.

Brittany was spotted on a luxurious yacht with at least four other ladies … soaking up the sun as they lounged on the back deck.

Britt rocked a tiny, orange two-piece for the occasion … which is something she’s quite accustomed to lately, as she was named to SI’s newest swimsuit issue back in February.

No word on what all the ladies got into … but chances are they had Taylor Swift’s new ‘Tortured Poets Department’ album blaring on the speakers, considering Brittany was super pumped for Travis Kelce’s girlfriend when the project dropped.

It was quite the eventful trip for the Mahomeses — as we previously reported, the couple was heckled by Raiders fans while out at dinner together last week.

But all good things come to an end … and same goes for the trip — after all, the next football season will be here before ya know it.