Mississippi's gaming age is twenty-one and there is no local variation.
What is restricted: the gaming floor. Slot banks, table games, the sports book. Under-21s may cross a floor to reach a restaurant, a lift or a pool, which in most of these buildings is unavoidable, but they may not stop, sit at a machine or stand watching a table. Security intervenes on lingering rather than on passing through.
What is not restricted: hotel rooms, pools, restaurants, cinemas, arcades, spas and, usually, shops. Showroom policies depend on the act rather than the venue, so ask when you buy tickets.
Identification. Expect to be asked, and expect it to be a real check rather than a glance, particularly at the sports book and the cage. Bring photo ID even if you have not been asked for it in twenty years.
Alcohol. The drinking age is also twenty-one. Coast casinos serve late and several run bars on or beside the floor.
Smoking is permitted on some floors here, which visitors from states with comprehensive bans notice immediately on walking in. At least one Back Bay property has long marketed itself as the coast's smoke-free casino. Policies do change, so if this matters to you, ring the property and ask rather than relying on anything written online, including this page.
Getting home. Rideshare covers the beach road well and surges hard when a showroom empties, because several thousand people leave one building at the same moment. Valet is usually free and is the simpler answer after a drink. Do not walk back along an unlit stretch of US 90 at two in the morning.