Don't Miss These Critical Medicare Deadlines!

Missing a Medicare deadline can have important long-term financial consequences. It may mean more money out of pocket for care, or higher penalty premiums for the rest of your life.


Initial Enrollment Period

Your initial enrollment period starts three months before the month in which you turn 65, and lasts until the end of the third month after the month in which you turn 65. Missing this initial enrollment window may result in late-enrollment penalties, unless you qualify for a special enrollment period.

Enrollment is automatic for Parts A and B, but if you want to enroll in a Medicare Advantage program or a Medicare Part D (prescription drug) plan, it's important to meet this deadline. But, don't wait until the month in which you turn age 65 to enroll. If you wait beyond the end of the month before you turn 65 to enroll in Part B, your Part B coverage could be delayed. This would result in a gap in your coverage. If you have a medical event before your Part B coverage kicks in, you could then face significant out-of-pocket expenses.

You can sign up at the Social Security office, or apply online at

Medicare Supplement (Medigap) Deadlines

Medicare Supplement plans, also known as "Medigap" policies, also impose enrollment deadlines. These are additional insurance policies from private carriers that help cover deductibles, copays and additional services that aren't covered under Medicare.

Typically, you have six months from the time you enroll in Medicare to purchase a Medigap policy and still get guaranteed acceptance, regardless of your medical condition. If you aren't in good health, your carrier could deny coverage altogether if you're not enrolled.

General Enrollment Period

If you don't sign up for Part A and Part B during your initial enrollment period, you can do so during the general enrollment period, which is between January 1 and March 31 each year. You'll have to pay additional penalty premiums, and your coverage won't begin until July 1.

Special Enrollment Period

You may be able to avoid late Medicare enrollment premiums and penalties under certain limited circumstances.

You may qualify for a special enrollment period if:

  • You or your spouse (or other family member if you're disabled) are working; or

  • You're covered by a group health plan (excluding COBRA and retiree health plans).

Switching Plan

If you want to join or switch your Medicare Advantage (Part C) or prescription drug (Part D) plan, you generally need to do so during the open enrollment period for these plans, from October 15 through December 7.

During this period, you can choose to do the following:

  • Switch from Original Medicare (Part A and B) to Medicare Advantage;

  • Switch from Medicare Advantage back to Original Medicare;