Medicare Enrollment Periods: When Can You Sign Up?

Key takeaways

The Initial Enrollment Period lasts 7 months: it starts 3 months before you turn 65 and ends 3 months after the month you turn 65.
If you miss it, you may have to wait to sign up and pay a monthly late enrollment penalty for as long as you have Part B.
The General Enrollment Period runs January 1 to March 31. Open Enrollment, for changing plans, runs October 15 to December 7.
If you are happy with your current Medicare coverage, you do not need to do anything during Open Enrollment.

The short answer

For most people, the first chance to sign up for Medicare is the Initial Enrollment Period. It lasts 7 months: it starts 3 months before you turn 65 and ends 3 months after the month you turn 65. Medicare.gov says that if you miss it, you may have to wait to sign up and pay a monthly late enrollment penalty for as long as you have Part B coverage.

The main enrollment periods

Period	When	What it is for
Initial Enrollment Period	7 months around your 65th birthday: the 3 months before, the month you turn 65, and the 3 months after	Your first chance to sign up for Medicare
General Enrollment Period	January 1 to March 31 each year	Signing up if you missed your Initial Enrollment Period
Open Enrollment	October 15 to December 7 each year	Changing your Medicare health or drug coverage. Changes take effect on January 1
Medicare Advantage changes	January 1 to March 31 each year	If you are in a Medicare Advantage plan, switching to a different one, or to Original Medicare with a separate drug plan

When your coverage starts

Medicare coverage always starts on the first day of a month. The date depends on which month you sign up during your Initial Enrollment Period. If you sign up in the month you turn 65, or during the 3 months after, coverage starts the next month.

If your birthday is on the first of the month, coverage starts the month before you turn 65.

If you are still working

Medicare says that if you sign up for Part B while you (or your spouse) are still working, or within the first full month after employer coverage ends, you can ask to delay your Part B start date up to 3 months. Check Medicare.gov for the rules that apply to your situation.

Open Enrollment is for changes

Open Enrollment is the time each year when you can make changes to your health or drug coverage. The plan must get your enrollment request by December 7. If you are happy with your current coverage, you do not need to do anything: Medicare says it continues automatically.

A short plan

Mark your 7-month window, starting 3 months before your birthday month.
Check whether you or your spouse still have coverage through work.
Decide what you need: Original Medicare, a Medicare Advantage plan, drug coverage.
Each fall, review your plan's changes during Open Enrollment.

Common mistakes

Waiting until after your Initial Enrollment Period ends.
Treating Open Enrollment as the way to sign up for the first time. It is for changing health or drug coverage.
Assuming you must act every fall. If you keep your coverage, it continues automatically.

General information only. It is not insurance, legal or financial advice. Rules differ by state and change over time, so confirm details with your state insurance department, your insurer and your policy.

Questions

What is the Initial Enrollment Period?

It is your first chance to sign up for Medicare, generally when you turn 65. It lasts 7 months: it starts 3 months before you turn 65 and ends 3 months after the month you turn 65.

What if I miss my first window?

You may have to wait to sign up, for example during the General Enrollment Period from January 1 to March 31, and pay a monthly late enrollment penalty for as long as you have Part B coverage.

Do I need to do anything during Open Enrollment?

Only if you want to change your coverage. Medicare says that if you keep your current health and drug coverage, it continues automatically.

Sources

Medicare.gov: When does Medicare coverage start?medicare.gov
Medicare.gov: Open Enrollmentmedicare.gov
Medicare.gov: Remember key Medicare dates (PDF)medicare.gov
HHS: Medicarehhs.gov

Informational only. Rules and policy terms change and differ by state and insurer. Confirm details with your policy, your insurer or your state insurance department.