Boston Logan International Airport (BOS) is technically open 24 hours a day, but with significant restrictions as of 2026. While the terminals (A, B, C, and E) remain accessible, a strict policy implemented in July 2024 prohibits using the airport as an overnight shelter for non-travelers. To stay overnight, you must demonstrate you are a legitimate traveler with a valid boarding pass or a confirmed connection. Note that TSA checkpoints close overnight (typically between 11:00 PM and 4:30 AM), so if you aren't already "airside," you must wait in the pre-security areas. Food services are also extremely limited after midnight, though 24/7 parking garages and airport hotels remain fully operational.