Hotels do not have curfews for their guests… although the local government might (health, riots, whatever reason they can think of). Some hotels do lock the lobby and other entrances at 11:00 pm, but your room key should open them.

Most modern hotels with a 24-hour reception keep their front doors unlocked throughout the day, but they typically electronically lock or "secure" the entrance between 11:00 PM and 6:00 AM. During these overnight hours, guests are usually required to use their active room key card to tap on an external sensor to open the automatic doors. This is a standard safety measure to prevent unauthorized individuals from wandering into the lobby while the staff is focused on night-audit duties or back-office tasks. If you are arriving for a late-night check-in, there is almost always a buzzer or an intercom at the door that connects you to the night porter, who will verify your reservation and let you in. Larger luxury hotels in major cities may keep their doors open 24/7 but will have a security guard stationed at the entrance to greet and vet visitors. In any case, as a registered guest, you never have to worry about a "curfew"—you always have 24-hour access to the building with your key card.