The first to board are suites, wedding parties, diamond, and then platinum followed by everyone else. When you select your time 10:30ami if you're lucky, then the mob is checked in, it's a zoo until about 1:00pm. The latest you can arrive depends what time you sail.If sail away is 5pm, final boarding is usually 3:30pm, I would not cut it that close. We are platinum and one time we came down on the train from Port St. Lucie. Had a rental car delay in West Palm Beach an hour train ride, arrived at the Port of Miami around 2pm, walked right on the ship