They were spotted in Key West, Florida, as they boarded onto a small boat with a group of friends.
Montana, 30, put his beach body on display as he went shirtless for the boat ride while Kardashian, 30, covered up in a sweater and a long dress, reported People magazine.
The rapper has been sharing snaps of his island vacation on Instagram, although he has yet to post a shot of Kardashian.
He did however show off his funny side, posting a picture of himself trying to hold a setting sun between his fingers but completely missing the mark.
Kardashian first stepped out with Montana last spring, but they had parted ways twice since then.