Medicare Annual Enrollment Period

You must have Medicare before you can enroll in a Medicare Advantage Plan or Drug plan (Part D). Outside Open Enrollment (October 15 - December 7) you can enroll only during specific times, like your Initial Enrollment Period or a Special Enrollment Period.

Outside Open Enrollment (October 15 - December 7) you can enroll in a Medicare Advantage Plan or drug plan, or make changes to coverage you already have only during these specific times:

Initial Enrollment Period (New to Medicare)

You can join a Medicare Advantage Plan or drug plan during the 7-month period that starts 3 months before the month you turn 65, includes the month you turn 65, and ends 3 months after the month you turn 65.

Special Enrollment Period
You may be able to join, switch, or drop your Medicare Advantage Plan and drug coverage when certain events happen in your life (like if you move or you lose other insurance coverage). Rules about when you can make changes and the type of changes you can make are different for each Special Enrollment Period.
Learn more about the circumstances that qualify you for a Special Enrollment Period.

Medicare Advantage Open Enrollment Period

January 1 - March 31 each year, you can make these changes:

If you're in a Medicare Advantage Plan (with or without drug coverage), you can switch to another Medicare Advantage Plan (with or without drug coverage).
You can drop your Medicare Advantage Plan and return to Original Medicare. You'll also be able to join a drug plan.

Note: If you enrolled in a Medicare Advantage Plan during your Initial Enrollment Period, you can change to another Medicare Advantage Plan (with or without drug coverage) or go back to Original Medicare (with or without a drug plan) within the first 3 months you have Medicare.

General Enrollment Period

If you didn't enroll in a plan during your Initial Enrollment Period, and you don't qualify for a Special Enrollment Period, you can enroll in a Medicare Advantage Plan or drug plan January 1 - March 31 each year. Your coverage won't start until July 1 of that year and you may have to pay a higher Hospital (Part A) and/or Medical (Part B) premium for late enrollment.

See the Medicare & You" handbook for more information about these Enrollment Periods.

https://www.medicare.gov/plan-compare/#/questions?year=2021&lang=en