Ansel Elgort, GF Ring in 2020 at Luxurious Dominican Republic Villa

Ansel Elgort hit up the perfect spot to ring in the New Year with his bikini-clad GF ... a villa in the Dominican Republic that had all the bells and whistles.

Ansel has spent a week in the luxurious beachside of Cap Cana. The actor clearly doesn't subscribe to the "twos company, threes a crowd mantra" ... because joining them on the trip was also Ansel's mom.

All good though ... cause there's plenty of space to spread around in this SICK villa. The rental pad -- known as Villa Las Hamacas -- is a $20 million estate featuring 6 bedrooms, an infinity pool and concierge service.

If the villa looks familiar ... it's cause Bella Thorne stayed in the same one just last month. It rents for a cool $15k per night ... but don't forget -- the rental includes a butler!!!

Ansel and his GF, Violetta Komyshan, have a knack for getting wild at some of the best beaches in the world. You'll recall the longtime couple was all over each other in Mexico around this time last year.

This time around, Ansel posted a picture of himself carrying Violetta and getting real handsy. He captioned it, "How you gon be mad on vacation?" Can't be mad ... especially after he was just named a presenter at this weekend's Golden Globe Awards.