Yes, you can check into a hotel at 1:00 AM, but only if you have a guaranteed reservation for the previous night and have notified the hotel of your "late arrival." In the hotel industry, the "business day" typically resets between 3:00 AM and 6:00 AM; therefore, a 1:00 AM arrival on Tuesday morning is technically still considered a Monday night stay. If you simply walk in at 1:00 AM without a booking, the hotel may have "run the night audit," and they might not be able to check you in until the official afternoon check-in time, or they may be fully booked. In 2026, many hotels utilize Digital Check-In via their mobile apps, allowing you to bypass the front desk and use your phone as a key. This is especially helpful for late arrivals, as it ensures your room is held and ready regardless of the hour. Always call ahead if you anticipate arriving after midnight, as some hotels may mark you as a "no-show" and release your room if you haven't checked in by 11:00 PM or midnight.