The couple, who are vacationing around the Mediterranean, were caught sharing an affectionate kiss as they rode a ferry to and from the tony Italian town, reported People magazine.
Packer, 47, a media mogul, held tight to Carey's hand as they explored the famed vacation spot.
The singer, 45, wore a patterned maxi dress for the stroll, pairing the longsleeve gown with cork wedges and big sunglasses. Carey's windswept, curly hair added to the relaxed vibe.