https://peps.python.org/pep-0790/

Expected:

3.15 development begins: Tuesday, 2025-05-06 3.15.0 alpha 1: Tuesday, 2025-10-14 3.15.0 alpha 2: Tuesday, 2025-11-18 3.15.0 alpha 3: Tuesday, 2025-12-16 3.15.0 alpha 4: Tuesday, 2026-01-13 3.15.0 alpha 5: Tuesday, 2026-02-10 3.15.0 alpha 6: Tuesday, 2026-03-10 3.15.0 alpha 7: Tuesday, 2026-04-07 3.15.0 beta 1: Tuesday, 2026-05-05 (No new features beyond this point.) 3.15.0 beta 2: Tuesday, 2026-05-26 3.15.0 beta 3: Tuesday, 2026-06-16 3.15.0 beta 4: Tuesday, 2026-07-14 3.15.0 candidate 1: Tuesday, 2026-07-28 3.15.0 candidate 2: Tuesday, 2026-09-01 3.15.0 final: Thursday, 2026-10-01

3.15 lifespan

Python 3.15 will receive bugfix updates approximately every second month for two years. Around the time of the release of 3.18.0 final, the final 3.15 bugfix update will be released. After that, it is expected that security updates (source only) will be released for the next three years, until five years after the release of 3.15.0 final, so until approximately October 2031.