In some photos, Patrick could be seen placing his hand on the 22-year-old pop star's shoulder as they walked by the pool.
The 'Wrecking Ball' singer wore a black plunging one-piece swimsuit paired with ripped denim hotpants. She completed her look with black sunglasses, a Chanel choker, gold bracelets and flat platform shoes.
Patrick, meanwhile, looked comfortable wearing a grey tee, printed shorts and white sneakers.
The couple was later spotted standing on their hotel balcony, smoking.
"Miley and Patrick partied together until 6am. After performing at the Art Basel, Miley reportedly headed to Miami's 24-hour show club, E11even Miami, along with her boyfriend," an onlooker said.