When and how you enroll in Medicare depends on your age and work history

You become may be able to access for Medicare at 65, and enrollment happens through Social Security, not through Medicare directly. Most people enroll automatically if they are already receiving Social Security benefits. If you are not yet receiving benefits, you must contact Social Security to start the process. The timing matters because missing your enrollment window can mean paying a permanent penalty on your premiums.

The enrollment process itself is straightforward: you provide basic information to Social Security, confirm your citizenship or legal residency, and choose your coverage. You do not need to visit an office — you can enroll online, by phone, or by mail. The key is understanding which enrollment period applies to you, because the rules differ depending on whether you are turning 65, already 65, or retiring at a different age.

Key Takeaways

  • Most people enroll through Social Security at age 65, either automatically if they already receive benefits or by contacting Social Security directly if they do not.
  • Your Initial Enrollment Period is the three months before the month you turn 65, the month you turn 65, and the three months after — missing this window triggers a permanent penalty.
  • You can enroll online at ssa.gov, by calling Social Security at 1-800-772-1213, or by visiting your local Social Security office in person.
  • If you are still working and have employer health coverage, you may be able to delay enrollment without penalty, but you must notify Social Security of your situation.

Your Initial Enrollment Period: The seven-month window

Your Initial Enrollment Period runs for seven months: three months before the month you turn 65, the month you turn 65 itself, and three months after. For example, if you turn 65 in June, your enrollment period is March through September. During this window, you can enroll in Medicare Part A (hospital insurance) and Part B (medical insurance) without penalty.

If you miss this seven-month window, you will pay a permanent surcharge on your Part B premium for as long as you have Medicare — typically 10 percent more per year for each year you delayed. There is no way to remove this penalty later, so enrolling on time matters financially. The only exception is if you had employer coverage or were still working when you turned 65; in that case, you may have a Special Enrollment Period that lets you enroll later without penalty.

Coverage typically begins on the first day of the month in which you turn 65, or the first day of the following month if you enroll after your birthday month. If you enroll in March for a June birthday, coverage starts June 1. If you enroll in July for a June birthday, coverage starts August 1.

How to enroll: Three ways to contact Social Security

Online enrollment is the fastest route. Visit ssa.gov, sign in to your my Social Security account (or create one), and look for the Medicare enrollment option. You will need your Social Security number, date of birth, and citizenship information. The online process takes about 15 minutes and you receive confirmation when ready.

Phone enrollment is available by calling Social Security at 1-800-772-1213. Representatives are available Monday through Friday, 7 a.m. to 7 p.m. in your local time zone. Have your Social Security number and birth certificate or passport ready. The call typically takes 20 to 30 minutes. If you call during peak hours (mid-morning or early afternoon), wait times can be long, so calling early morning or late afternoon often moves faster.

In-person enrollment at your local Social Security office is an option if you prefer to enroll face-to-face. Find your nearest office at ssa.gov/locator. Bring your Social Security card, proof of citizenship (passport, birth certificate, or naturalization papers), and proof of residency (utility bill or lease). You do not need an appointment at most offices, but you can schedule one online to avoid waiting.

What information you will need to provide

Social Security will ask for your full legal name, date of birth, Social Security number, and citizenship or legal residency status. Have your Social Security card or a document showing your number. You will also confirm your mailing address and provide a phone number where they can reach you.

If you are enrolling by phone or online, you will not need to submit documents at that moment — Social Security already has most of this information on file. If you are enrolling in person, bring proof of citizenship (a U.S. passport is easiest, but a birth certificate or naturalization papers work). If you were born outside the United States and are a permanent resident, bring your green card or I-94 arrival record.

Choosing between Part A and Part B, and adding Part D or Part C

When you enroll, you are choosing whether to take Part A (hospital insurance) and Part B (medical insurance). Most people take both. Part A is usually free if you or your spouse paid Medicare taxes for at least 10 years. Part B requires a monthly premium, which varies by income but is typically around $165 to $560 per month in 2024 (the amount changes yearly).

At the same time, you can choose to add Part D (prescription drug coverage) through a private insurance company, or you can choose a Part C plan (Medicare Advantage) instead of Original Medicare. Part C is an all-in-one alternative offered by private insurers that combines Parts A, B, and usually D. If you do not choose Part D when you first enroll and you do not have other drug coverage, you will pay a permanent penalty if you add it later.

You do not have to decide on Part C or Part D during your Initial Enrollment Period — you can add them during the Annual Enrollment Period (October 15 to December 7 each year) or during other Special Enrollment Periods. However, if you want Part D from the start, enroll during your Initial Enrollment Period to avoid the penalty.

If you are still working or have employer coverage

If you are still working and your employer offers health insurance, you may be able to delay enrolling in Part B without penalty. This is called creditable coverage. You must notify Social Security that you have employer coverage and do not want to enroll in Part B yet. When you eventually retire and lose that coverage, you will have an eight-month Special Enrollment Period to enroll in Part B without penalty.

To claim this exception, contact Social Security during your Initial Enrollment Period and tell them you want to delay Part B because you have employer coverage. Ask them to note this in your file. You will receive a notice confirming your choice. Keep this notice — you will need it when you enroll in Part B later to prove you were covered and did not miss your important date.

Part A enrollment is separate from Part B. Even if you delay Part B, you should still enroll in Part A during your Initial Enrollment Period, because Part A is usually free and covers hospital stays. Delaying Part A can result in a penalty.

After you enroll: What happens next

After you enroll, Social Security will mail you a Medicare card within two to four weeks. Your coverage begins on the date Social Security confirms, usually the first of a month. You can also view your Medicare information online through Medicare.gov by creating an account with your Social Security number and email address.

If you chose Original Medicare (Part A and Part B), you will receive your red, white, and blue Medicare card in the mail. If you chose a Part C plan, your new insurance company will send you a card for that plan. If you added Part D, your prescription drug plan will send a separate card.

Once your coverage starts, you can use your Medicare benefits at any hospital, doctor's office, or pharmacy that accepts Medicare. If you chose a Part C plan, your coverage works differently — you must use doctors and hospitals in your plan's network, similar to an HMO or PPO.

Frequently Asked Questions

What if I turn 65 but am not ready to retire yet?

You can still enroll in Medicare at 65 even if you keep working. If your employer offers health insurance, you may be able to delay Part B without penalty by notifying Social Security that you have creditable coverage. Part A enrollment is still recommended because it is usually free and covers hospital stays if you need them.

Can I enroll in Medicare before I turn 65?

No. You can begin the enrollment process up to three months before you turn 65, but your coverage will not start until the month you turn 65 or the month after, depending on when you enroll. If you have end-stage renal disease or ALS, different rules explore — contact Social Security to learn about your options.

What if I miss my Initial Enrollment Period?

You can still enroll during the General Enrollment Period (January 1 to March 31 each year), but you will pay a permanent 10 percent surcharge on your Part B premium for each year you delayed. The only way to avoid this penalty is if you had employer coverage or may have access to for a Special Enrollment Period — contact Social Security to learn about you do.

Do I need to enroll in Part D when I first turn 65?

You do not have to, but if you do not have other prescription drug coverage and you do not enroll in Part D during your Initial Enrollment Period, you will pay a permanent penalty if you add it later. If you have coverage through an employer or union, you may be able to delay without penalty — ask your benefits administrator whether your coverage is creditable.

Can I change my mind after I enroll?

Yes. You can make changes during the Annual Enrollment Period (October 15 to December 7) or if you experience a may have access to life event like losing employer coverage, moving, or getting married. Contact Social Security or Medicare.gov to learn about your options for changes.