Joe Jonas is not one to be left in the dust while his ex, Sophie Turner, moves on following their bitter split ... spotted boarding a private jet with a stunning model.

After ringing in the New Year in Los Cabos, the singer linked up with former Miss Teen USA titleholder Stormi Bree Wednesday ... which is sure to kickstart some romance rumors.

It's the first time we've seen the two together -- and they don't even follow each other on IG -- so they may be trying to keep things under the radar.

Either way, after some downtime in Mexico, it's likely Joe's heading home to NYC ... as Sophie has to drop their kids off to him on Jan. 7 after she spent Xmas and New Year's with them.

Unclear if the former "Game Of Thrones" star introduced the youngsters to her new BF, British aristocrat Peregrine Pearson, during the holidays.

The new couple were hot and heavy from the get-go ... kissing in Paris just one month after Joe filed for divorce from Sophie in September ... and later lockin' lips some more during a cozy London stroll in early December.

Joe's clearly taking things a little slower ... but it may just be a matter of time before he gets in some serious smoochin' with Stormi!