What to know

  • Different enrollment periods control different actions.
  • The fall Open Enrollment Period is not the first chance to sign up for Part B.
  • Special Enrollment Periods depend on specific qualifying circumstances.

Initial Enrollment Period

For most people first eligible at 65, this seven-month window begins three months before the birthday month and ends three months after it. Coverage start timing depends on when enrollment occurs.

Special and General Enrollment Periods

A Special Enrollment Period may apply after active-employment group coverage ends or following another qualifying event. The General Enrollment Period is available each year for certain people who missed earlier opportunities; penalties may apply.

Plan election periods

Medicare’s fall Open Enrollment Period and the Medicare Advantage Open Enrollment Period concern plan changes. They are not substitutes for every Part A or Part B enrollment deadline.