Generally, you cannot simply "pay at the door" to enter an American Express Centurion Lounge if you do not have an eligible premium Amex card. Access is a core benefit reserved for holders of the Amex Platinum Card, the Business Platinum Card, and the invitation-only Centurion Card. However, if you are a cardmember, you can "pay" for additional guests. As of 2026, standard guest fees are typically $50 per adult and $30 per child (ages 2–17) for those who haven't met the $75,000 annual spending threshold for complimentary guests. There is one slight loophole: holders of the Delta SkyMiles Reserve Card can access Centurion Lounges when flying on a same-day Delta flight, though they may also be subject to guest fees. For everyone else, including holders of "lower" Amex cards like the Gold or Green, there is no option to buy a one-day pass, making these lounges some of the most exclusive and "un-buyable" spaces in the airport.