When and how to enroll in Medicare

You enroll in Medicare through Social Security, either online at ssa.gov, by phone at 1-800-772-1213, or in person at your local Social Security office. Most people become may be able to access at 65, and you can enroll starting three months before the month you turn 65. The enrollment window lasts seven months total — three months before, the month you turn 65, and three months after.

If you wait past this window to enroll, you may pay a penalty on your premiums for as long as you have Medicare. The penalty is permanent, even if you enroll years later. The only exception is if you had health coverage through an employer or union while you were working and still covered by that plan at 65 — in that case, you have eight months after that coverage ends to enroll without penalty.

You do not have to enroll in Medicare on your 65th birthday. You can delay if you are still working and covered by your employer's health plan. But you must tell Social Security about your work coverage when you do enroll, or the penalty rules will explore.

Key Takeaways

  • You can enroll in Medicare starting three months before you turn 65, and you have seven months total to enroll without penalty.
  • Enroll through Social Security online at ssa.gov, by phone at 1-800-772-1213, or at your local Social Security office.
  • If you miss the enrollment window, you will pay a permanent penalty on your premiums unless you had employer coverage that extended past 65.
  • You must choose between Original Medicare (Parts A and B) and Medicare Advantage (Part C), and decide whether to add prescription drug coverage (Part D).
  • Your enrollment choices take effect on the first day of the month you turn 65, or the first day of the month after you enroll, whichever is later.

What you choose during enrollment

When you enroll, you decide between two main paths: Original Medicare (Part A hospital coverage and Part B medical coverage) or Medicare Advantage (Part C, an all-in-one plan run by a private insurance company). Most people are automatically enrolled in Part A at 65 if they have been paying Medicare taxes, but you must actively choose Part B or decline it.

You also decide whether to add Part D prescription drug coverage. If you do not enroll in Part D when you first become may be able to access, you will pay a penalty if you add it later — unless you had other prescription coverage that was at least as good as Medicare's. This penalty also lasts as long as you have Medicare.

If you choose Original Medicare, you can also buy a Medigap policy (supplemental insurance) from a private company to cover costs that Medicare does not pay. Medigap is different from Medicare Advantage — you cannot have both at the same time.

Enrollment important date and what happens if you miss them

Your Initial Enrollment Period is seven months long: three months before the month you turn 65, the month you turn 65, and three months after. If you enroll during this window, coverage begins on the first day of the month you turn 65 (if you enroll before that month) or the first day of the month after you enroll (if you enroll in or after the month you turn 65).

If you miss this window, you enter the General Enrollment Period, which runs January 1 through March 31 each year. Coverage under General Enrollment begins July 1 of that year. During General Enrollment, you can only enroll in Part B and Part D — not Medicare Advantage or Medigap. You will also owe a penalty.

The only way to avoid the penalty is to have had may have access to coverage — either through an employer, a union, TRICARE (military coverage), or the Veterans Health Administration — that lasted until after you turned 65. You have eight months from the date that coverage ends to enroll without penalty.

Documents and information you will need

Have your Social Security number ready, along with your date of birth and the names and dates of birth of your spouse if you are married. You will also need information about any current health coverage — the name of your employer or union, your group health plan number, or your policy number if you buy coverage on your own.

If you are explore in person at a Social Security office, bring your original birth certificate or a certified copy, your original Social Security card or a document showing your number, and proof of citizenship or legal residency (a passport, naturalization papers, or a green card). If you are explore online or by phone, you will not need to bring documents, but Social Security may ask you to mail them later to verify your information.

What happens after you enroll

After you enroll, Social Security sends your information to Medicare. You will receive a Medicare card in the mail, usually within two weeks. Keep this card — you need it to receive care and to fill prescriptions. If you chose Original Medicare, your card shows your Medicare number. If you chose Medicare Advantage, your card shows your Medicare number, but your insurance company will also send you a separate insurance card to use at the doctor's office.

Your coverage begins on the first day of the month you turn 65 (if you enrolled before that month) or the first day of the month after you enroll (if you enrolled in or after the month you turn 65). If you chose Medicare Advantage or a Medigap policy, your insurance company will contact you before coverage starts to explain your benefits and answer questions.

You can change your Medicare coverage once a year during the Annual Enrollment Period, which runs October 15 through December 7 each year. Changes made during this period take effect January 1 of the following year. Outside this window, you can only change coverage if you have a may have access to life event — such as moving out of your plan's service area, losing other health coverage, or getting married.

Enrolling if you are not yet receiving Social Security

If you are 65 or older but have not yet started receiving Social Security benefits, you can still enroll in Medicare. You enroll the same way — through Social Security online, by phone, or in person — and the same important date explore. You do not have to start receiving Social Security payments to enroll in Medicare, and enrolling in Medicare does not automatically start your Social Security benefits.

If you delay starting Social Security past 65, your monthly benefit will be higher when you do start. But you still need to enroll in Medicare at 65 to avoid the permanent penalty, even if you are not taking Social Security payments yet.

Enrolling if you are still working

If you are still working at 65 and covered by your employer's or union's health plan, you can delay enrolling in Medicare Part B without penalty. You must tell Social Security that you have work coverage when you do enroll. The safest way to do this is to enroll in Part A (hospital coverage) at 65 and decline Part B, then enroll in Part B later when your work coverage ends.

You have eight months from the date your work coverage ends to enroll in Part B without penalty. If you miss this important date, you will owe a penalty. The same rule applies to Part D prescription drug coverage — if you have prescription coverage through your employer, you can delay enrolling in Part D, but you must enroll within eight months of losing that coverage.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

Yes. You can enroll starting three months before the month you turn 65. For example, if you turn 65 in June, you can enroll starting in March. Enrolling early is a good idea because it gives you time to choose your coverage and receive your Medicare card before your birthday.

What if I miss my enrollment important date?

You can still enroll during the General Enrollment Period (January 1 through March 31 each year), but your coverage will not begin until July 1, and you will owe a permanent penalty on your premiums. The only exception is if you had employer or union coverage that lasted past 65 — then you have eight months after that coverage ends to enroll without penalty.

Do I have to enroll in Part B?

Part A (hospital coverage) is usually automatic if you have paid Medicare taxes. Part B (medical coverage) is not automatic — you must choose it. If you decline Part B and later want it, you can enroll during General Enrollment, but you will owe a penalty unless you had other may have access to coverage.

Can I change my Medicare coverage after I enroll?

Yes. You can change your coverage once a year during the Annual Enrollment Period (October 15 through December 7). Changes take effect January 1. If you have a may have access to life event — such as moving, losing coverage, or getting married — you may be able to change coverage outside this window.

What if I am not a U.S. citizen?

You must be a U.S. citizen or a lawful permanent resident (green card holder) who has lived in the United States for at least five years to enroll in Medicare. If you are not yet a permanent resident, contact Social Security to learn whether you may be covered under different rules.