When You Can Sign Up for Medicare Part B

Medicare Part B enrollment windows depend on when you turn 65 and whether you already have coverage

You have three main enrollment windows for Medicare Part B: your Initial Enrollment Period (IEP), which is seven months centered on your 65th birthday; General Enrollment Period (GEP), which runs January 1 through March 31 each year; and Special Enrollment Periods (SEP), which open if you lose employer coverage or move to a new state. Missing your IEP without a valid reason usually means paying a permanent penalty on your Part B premium for as long as you have Medicare.

The window you use matters because it determines when your coverage starts and whether you owe extra money. Most people should sign up during their IEP to avoid penalties, but the rules are different if you are still working, covered by an employer plan, or moving from another state.

Key Takeaways

Your Initial Enrollment Period runs for seven months: three months before your 65th birthday, the month you turn 65, and three months after.
If you miss your IEP and have no employer coverage, you can sign up during General Enrollment (January 1 through March 31), but coverage does not start until July 1 and you will owe a penalty.
If you are still working and covered by your employer's health plan, you can delay Part B without penalty as long as you sign up within eight months of losing that coverage.
You sign up through Social Security (online at ssa.gov, by phone at 1-800-772-1213, or in person at your local office), not through Medicare directly.
Special Enrollment Periods are available if you move states, lose employer coverage, or have other may have access to life changes — contact Social Security to learn if you are may be able to access.

Your Initial Enrollment Period: the seven-month window around your 65th birthday

Your IEP starts three months before the month you turn 65 and ends three months after. For example, if you turn 65 in June, your IEP runs from March through September. This is the window Social Security recommends because signing up during this time means your coverage starts the first day of the month you turn 65 (or the first day of the following month if you sign up in your birth month itself).

You do not have to wait until your birthday month to act. Many people sign up in the first month of their IEP to avoid forgetting the important date. Signing up early does not change your start date — it will still be the first of your 65th birthday month — so there is no downside to getting it done sooner.

If you sign up after your birth month but still within your IEP, coverage typically starts the first day of the month after you sign up. For instance, if you turn 65 in June and sign up in August, your Part B coverage would start September 1.

General Enrollment Period: January 1 through March 31 each year

If you miss your IEP, you can sign up during General Enrollment, which happens every year from January 1 through March 31. However, there are two significant costs to waiting: your coverage does not start until July 1 of that year, and you will owe a late enrollment penalty added to your monthly premium for as long as you have Part B.

The penalty amount depends on how long you went without Part B coverage. For each full year you could have had Part B but did not, your premium increases by 10 percent. If you were supposed to sign up at 65 and did not sign up until age 68, for example, you would owe a 30 percent penalty. This penalty does not expire — it stays on your bill every month.

Because of this penalty, General Enrollment should be your backup plan, not your first choice. It exists for people who genuinely did not know about the important date or had circumstances that prevented them from signing up on time.

Special Enrollment Periods: when you can sign up outside the regular windows

A Special Enrollment Period lets you sign up for Part B at any time of year without waiting for January and without owing a penalty, but only if you have a may have access to reason. The most common may have access to reasons are losing employer health coverage, moving to a different state, or having a change in your immigration status.

If you are still working at 65 and your employer offers health insurance, you can delay Part B without penalty. You have eight months from the date you lose that employer coverage to sign up for Part B. This is called the employer coverage exception, and it is one of the most important rules for people who work past 65. You must sign up within that eight-month window, or you will owe the late enrollment penalty.

Other may have access to events include moving to a new state (which may change which Medicare plans serve your area), losing Medicaid coverage, or becoming a U.S. citizen or lawful permanent resident. If you think you have a may have access to reason, contact Social Security to ask whether a Special Enrollment Period applies to you.

How to sign up: Social Security is your enrollment point

You sign up for Part B through Social Security, not through Medicare directly. You have three ways to do this: online at ssa.gov, by phone at 1-800-772-1213 (TTY 1-800-325-0778), or in person at your local Social Security office.

Online enrollment is usually the fastest option. You will need your Social Security number and basic information about your current health coverage (if you have any). The Social Security website lets you check the status of your process and see your enrollment confirmation.

If you call or visit in person, a Social Security representative will walk you through the process and answer questions about your specific situation. Wait times can be long during peak enrollment periods (October through December and January through March), so calling early in the day or visiting early in the week may be faster.

What happens if you miss your important date

If you miss your IEP and have no employer coverage, you will have to wait until the next General Enrollment Period to sign up. Your coverage will not start until July 1, and you will owe a permanent penalty. The longer you wait after your IEP ends, the higher your penalty will be.

The only way to avoid the penalty is to have a may have access to reason for the delay. If you were working and covered by an employer plan, or if you moved states, or if you had another may have access to life event, you may be able to sign up during a Special Enrollment Period without penalty. You will need to provide proof of the may have access to event — such as a letter from your employer confirming the end date of coverage, or a lease or utility bill showing your new address.

If you are unsure whether you have a may have access to reason, contact Social Security before the important date. It is better to ask and learn you do not may have access to than to miss the important date and owe a penalty you could have avoided.

Frequently Asked Questions

Can I sign up for Part B before I turn 65?

Yes. Your Initial Enrollment Period starts three months before your 65th birthday, so you can sign up as early as that date. Many people sign up three or four months before their birthday to make sure they do not miss the important date. Your coverage will not start until the first of your 65th birthday month, regardless of when you sign up during your IEP.

What if I am still working at 65 and have health insurance through my job?

You can delay Part B without penalty as long as you sign up within eight months of losing your employer coverage. This is called the employer coverage exception. You do not have to sign up at 65 if you are still covered by an active employer plan, but you must sign up within that eight-month window after your coverage ends, or you will owe a late enrollment penalty.

Do I have to sign up for Part A and Part B at the same time?

No. Part A (hospital insurance) is usually automatic at 65 if you are receiving Social Security, but Part B (medical insurance) requires you to sign up. You can enroll in Part B separately and at a different time than Part A, though most people sign up for both during their Initial Enrollment Period.

What if I move to a different state after I turn 65?

Moving to a new state is a may have access to reason for a Special Enrollment Period. This matters because different states have different Medicare plans available. If you move, contact Social Security to report your new address and ask whether you need to make any changes to your Part B coverage or choose a new plan.

Can I sign up for Part B online, or do I have to call Social Security?

You can sign up online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office. Online enrollment is usually fastest. If you have questions about your specific situation, calling or visiting in person lets you speak with a representative who can help.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.