The 28-year-old reality star -- who's been hard at work at the gym and making healthier changes to his diet -- appeared noticeably slimmer as he made his way through Los Angeles International Airport with his girlfriend, Blac Chyna, late Saturday night.
Rocking a black Adidas hoodie, matching drawstring pants and a Los Angeles Dodgers baseball cap, weight loss was apparent as he hopped a red-eye to Montego Bay, Jamaica, with the 27-year-old model.
On Sunday, the two were spotted arriving along with a friend at Jamaica's Sangster International Airport. There didn't appear to be any on-flight clothing changes -- a frequent occurrence amongst the Kardashian clan.
Rob and Chyna didn't display any overt PDA, but an eyewitness tells ET that they were cheery and chatty while stepping into their limousine, which took them to a five-star beachfront resort on the island's northern coast. At one point, Chyna even pulled out her phone to snap a few selfies with her beau.
A few hours later, the duo attended the Caribbean Spring Break festival Brit Jam 2016, where Chyna was the guest of honor.
As ET previously reported, Chyna has played a significant role in Rob's "health and fitness journey," as Rob's sister, Khloe Kardashian, likes to call it.
On Friday, Rob took to Instagram to share a photo of a healthy date night meal Chyna had cooked for him, which consisted of Cornish hen, carrots and asparagus. He simply captioned the now-deleted snap with a chicken emoji. Chyna, on the other hand, shared the step-by-step secrets to her creation on Snapchat.