For Royal Caribbean cruises in 2026, you must board during the specific arrival window you selected during your digital check-in on the Royal Caribbean app. These windows typically start around 10:30 AM or 11:00 AM and run through the early afternoon. The "hard rule" is that all guests must be checked in and physically onboard the ship no later than 90 minutes before the scheduled departure time listed on your cruise documents. If the ship is set to sail at 4:30 PM, you must be on the ship by 3:00 PM at the absolute latest, or you will be denied boarding without a refund due to government manifest regulations. Royal Caribbean strongly encourages completing the app check-in up to 45 days in advance to secure an early boarding slot, which allows you to enjoy the ship’s buffet and pools before the crowds arrive. In 2026, the boarding process is almost entirely paperless, requiring only your "SetSail Pass" on your phone and your passport for a quick biometric scan at the terminal.