In 2026, you generally cannot use a United Club lounge unless you are flying on a same-day flight with United, a Star Alliance partner, or a contracted partner airline. This policy, which was tightened in recent years, requires all guests—including United Club members and one-time pass holders—to present a valid boarding pass for a qualifying flight. If you are flying on a non-partner airline like Delta or American, your United Club membership will not grant you entry. However, there are minor exceptions for United Club All Access members when visiting certain partner lounges abroad, but even then, a Star Alliance boarding pass is typically required. For those with a "One-Time Pass" from a credit card, the same rules apply: no qualifying boarding pass means no entry, and as of May 2025, these passes can only be used within three hours of your scheduled departure time unless you are on a connection.