Real estate sources tell TMZ ... the "Celebrity IOU: Joyride" host sold his 3-bedroom, 2-bath, 1,968-square-foot Laguna Beach pad on Monday with the closing price of $3.1 million. Ant bought the place for $2.8 million a few years back.

We're told he plans to find a new place in Laguna, although he hasn't found the right spot to call home just yet -- but he's not the only one leaving his old block.

Our sources say Ant's GF Renée Zellweger moved out of the house across the street from Ant's home last summer. As we reported, Renée started renting that place in November 2021 for $30k/month.

You'll recall, the Discovery+ personality listed his pad in October of last year and began storing his stuff at Renée's home.

At the time, our sources made it clear, Ant's intentions were NOT to move in with her ... and we're told that's still the case.

Whoever snagged Ant's now-former pad got quite the spread -- it has cool features like vaulted ceilings, a brick fireplace for those SoCal winter nights (climate change, bro) and a sunroom that can be transformed into a studio.

Plus, there's a wraparound deck to take in incredible Pacific Ocean views -- those are great year-round, even in the winter.