Justin Bieber and Hailey Baldwin partied like it was 2015 ... looking very much like a couple turning up all over Miami.
The Biebs and Hailey were spotted hanging out down in M-I-A on Sunday ... first hitting up a church conference before chowin' down at the ritzy Casa Tua, and then hitting up LIV Nightclub at Fontainebleau.
Our sources say Justin and Hailey walked in together around 1 AM ... where they hung out on a VIP balcony, held hands and danced together. They were definitely not trying to keep things on the DL ... showing plenty of PDA for all to see.
Justin goofed around a bit too ... busting out the Floss dance as the crowd cheered him on.
We're told Hailey and Justin left the club around 3 AM holding hands.
As we first reported, Hailey was the reason Justin and Selena Gomez ended up in couples therapy back in December -- after he tried to clear the air with Hailey about their brief relationship.