• Annual Enrollment (AEP) — not this date
  October 15 – December 7, 2026
  If you already have Medicare, this is the yearly window to change Medicare Advantage or Part D for January 1. It is not Medigap Open Enrollment.
• Medicare Advantage Open Enrollment — not this date
  January 1 – March 31, 2026
  If you start the year in a Medicare Advantage plan, you may make one change to another Advantage plan or back to Original Medicare (with Part D if you need it).

Windows can depend on facts this form cannot see (a move, Extra Help, a trial right). Confirm on Medicare.gov or with Social Security.