Medicare has four primary enrollment periods. Each has its own name, its own timing, and its own rules about what you can do. Here is each one, in plain language.

When you first become eligible (Initial Enrollment Period — IEP)

Your Initial Enrollment Period spans seven months: the three months before your 65th birthday month, your birthday month, and the three months after. Enrolling early in the window helps your coverage start on time.

Every fall: October 15 – December 7 (Annual Enrollment Period — AEP)

During the Annual Enrollment Period, anyone with Medicare can switch, add, or drop Medicare Advantage and Part D drug plans. Changes take effect January 1.

Early each year (Medicare Advantage Open Enrollment Period — OEP)

From January 1 to March 31, people already enrolled in a Medicare Advantage plan may make one change — switching to another Medicare Advantage plan or returning to Original Medicare.

When life changes (Special Enrollment Period — SEP)

Certain life events — such as moving out of your plan’s service area or losing employer coverage — open a Special Enrollment Period, allowing changes outside the standard calendar. If something in your life has recently changed, it is worth confirming your options.

If you are not sure which enrollment period applies to you, I’m happy to help you sort it out.