In Croatia, as in many European countries, the checking-in in the hotel, a villa or apartment is in the afternoon, while leaving is in the morning (before lunch). This is due to the fact that in high season, you need to clean quickly the rooms and prepare them for the next guests.
If it is low season, the hotels, as well as owners of private buildings, try to meet the needs of their guests - for example, late departure, allowing them to linger longer.