Kristin Cavallari Gets Close With 'Southern Charm' Star Austen Kroll on Spain Vacation

Kristin Cavallari is living her best life in Spain, but it's not just the sunshine turning up the heat ... the internet can't stop talking about who she's vacationing with -- "Southern Charm" star Austen Kroll.

Kristin also had her bestie, Justin Anderson, in tow ... and while she's never suggested she and Austen are anything more than friends, the two sure are photogenic together.

The reality TV stars even jumped off their yacht together ... holding hands as they splashed down in the beautiful blue waters off the coast of Mallorca.

No shame in Kristin's bikini body game ... the hot mom of three hit the back of the boat for some good ole' fun ... sporting an itsy bitsy teeny weeny polka dot bikini.

Kristin recently talked about staying single on her podcast ... explaining she's become more selective about her relationships. She's been friendly with Austen for years, so it's no lock he makes it out of the friend zone -- if he's even trying.