When Do United Miles Expire? United Airlines announced on August 28, 2019, that United miles will no longer expire—in most cases. Previously, miles expired after 18 months of account inactivity. United required MileagePlus members to earn or redeem miles at least once every 18 months to reset the clock.

United Airlines officially announced that MileagePlus miles never expire on August 28, 2019. This was a landmark move that followed similar policies from Delta and Southwest, making United more competitive for casual travelers who may only fly once every few years. Your miles will remain in your account indefinitely as long as your account remains open and in "good standing" (not involved in fraudulent activity). While the miles themselves don't expire, it is a "pro-tip" to remember that their purchasing power can devalue over time as airlines adjust "award charts." In 2026, while you don't have to worry about a "use it or lose it" deadline, it is still best to redeem your miles for high-value international flights or upgrades rather than letting a massive balance sit for a decade, as the "cost" of those flights in miles is likely to increase as the years go by.