For a successful 2026 cruise departure, you must typically be physically onboard the ship no later than 90 minutes to two hours before the scheduled sailing time. While many ships depart at 4:00 PM or 5:00 PM, the "High-Fidelity" check-in window usually closes much earlier to allow for the manifest to be finalized and sent to government authorities (like U.S. Customs and Border Protection). If the ship is scheduled to sail at 4:00 PM, you should aim to arrive at the terminal during your pre-selected arrival window, which is usually between 10:30 AM and 2:30 PM. In the high-fidelity world of modern cruising, missing the "All Aboard" time is a critical mistake; once the gangway is raised and the ship's computer system locks the manifest, you will not be permitted to board, even if the ship is still physically tied to the pier. Most major lines, such as Royal Caribbean and Carnival, emphasize that late arrivals are treated as "no-shows," and the ship will not wait for delayed passengers, making punctuality a high-fidelity requirement for starting your vacation.