explore during your initial enrollment period, which starts three months before the month you turn 65

Your Initial Enrollment Period (IEP) lasts seven months total: three months before the month you turn 65, the month you turn 65, and three months after. If you turn 65 in June, your window opens in March and closes in September. You can explore online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

If you miss this window, you can still enroll, but you will face a late enrollment penalty — a permanent increase to your Part B and Part D premiums that lasts as long as you have Medicare. The penalty grows the longer you wait. For every 12 months you delay Part B enrollment after your IEP ends, your premium increases by 10 percent. For Part D (prescription drug coverage), the penalty is roughly 1 percent of the national base premium for each month you were without coverage.

There are exceptions to this rule. If you have been covered by an employer or union health plan while working, or if your spouse is still working and covers you under their plan, you may have a different important date. You can enroll without penalty during the eight-month period after that coverage ends, as long as you enroll within 63 days of losing the coverage.

Key Takeaways

  • Your Initial Enrollment Period is seven months long: three months before you turn 65, the month you turn 65, and three months after.
  • Missing your enrollment window triggers a permanent penalty on Part B and Part D premiums that increases the longer you wait.
  • If you have employer or union coverage, you can delay Medicare enrollment without penalty as long as you enroll within 63 days of losing that coverage.
  • You can enroll online at Medicare.gov, by phone at 1-800-MEDICARE, or at your local Social Security office.
  • If you are still working at 65 and your employer has 20 or more employees, you may not need to enroll in Part B right away.

What happens if you are still working at 65

If you are still employed and your employer has 20 or more employees, you can delay Part B enrollment without penalty. This is called creditable coverage. You must enroll in Part A (hospital insurance) when you turn 65, but you can wait on Part B until you leave your job or lose your employer coverage.

When you do leave work, you have eight months to enroll in Part B without triggering a late penalty. The eight-month clock starts the month after your employment ends or your employer coverage stops, whichever comes first. If your employer has fewer than 20 employees, the rules are different — you should enroll in Part B when you turn 65 even if you are still working.

Part D (prescription drug coverage) follows the same rule as Part B: if you have creditable drug coverage through your employer, you can delay Part D enrollment. Once you lose that coverage, you have 63 days to enroll in Part D without a penalty.

Enrolling before 65 if you receive Social Security or railroad retirement benefits

If you already receive Social Security retirement or railroad retirement benefits, Medicare will enroll you automatically in Part A and Part B three months before the month you turn 65. You do not need to do anything — your coverage starts the month you turn 65. You will receive your Medicare card in the mail about two weeks before your coverage begins.

If you do not want Part B coverage when you turn 65, you must decline it in writing. This is rare, but it matters if you have employer coverage and do not want to pay for both. You can decline Part B by contacting Social Security before your coverage starts.

If you do not yet receive Social Security benefits, you will need to enroll in Medicare yourself during your Initial Enrollment Period. You cannot rely on automatic enrollment.

Special enrollment periods if you miss your important date

If you miss your Initial Enrollment Period and do not have an exception, you may still have a path forward through a Special Enrollment Period (SEP). These are limited windows that open for specific situations: you moved out of your Medicare plan's service area, your plan was discontinued, you were in prison, or you lost employer coverage.

The most common SEP is the one triggered by losing employer or union coverage. You have eight months from the date your coverage ends to enroll in Part B without penalty. For Part D, the window is 63 days. You will still owe the late penalty for any months between your Initial Enrollment Period and the date you actually enroll, but the SEP prevents the penalty from growing further.

If none of these situations explore to you, you can still enroll in Medicare during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage begins July 1 of that year. However, you will owe the late penalty for every month you were without coverage since your Initial Enrollment Period ended.

How to enroll and what documents you will need

You can enroll through three channels: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. Online enrollment is usually the fastest — you can complete it in 10 to 15 minutes if you have your information ready.

Have your Social Security number, birth date, and citizenship or immigration status available. If you are enrolling in Part D (prescription drug coverage), have a list of your current medications and the pharmacies you use. This helps you choose a plan that covers your drugs at the lowest cost. You do not need to bring original documents to enroll, but Social Security may ask you to mail copies later to verify your information.

If you enroll by phone, a representative will walk you through the same questions. If you go in person, bring your Social Security card and a photo ID. The process takes about 30 minutes at a Social Security office.

What to do if you turned 65 and do not remember when you enrolled

If you are unsure whether you enrolled in Medicare, you can check your status online at Medicare.gov by signing into your account, or you can call 1-800-MEDICARE. A representative can tell you which parts of Medicare you are enrolled in and when your coverage started.

If you discover you missed your enrollment important date and did not may have access to for an exception, you can still enroll during the next General Enrollment Period (January 1 through March 31). Your coverage will begin July 1, and you will owe the late penalty. The sooner you enroll, the sooner the penalty stops growing.

Frequently Asked Questions

What if I turn 65 in the middle of the month?

Your Initial Enrollment Period is based on the calendar month you turn 65, not the specific date. If you turn 65 on June 15, your enrollment period runs from March through September. You can enroll any time during those seven months, and your coverage will start on the first day of the month you turn 65 (June 1 in this example).

Do I have to enroll in Part B if I do not want it?

No, but if you decline Part B and later change your mind, you will owe a late penalty unless you have an exception. The only way to avoid the penalty is to enroll during your Initial Enrollment Period or within eight months of losing employer coverage. If you are unsure, it is safer to enroll and then cancel later if you do not need it.

Can I change my Medicare plan after I enroll?

Yes. You have an annual enrollment period from October 15 through December 7 each year when you can switch plans. You can also switch plans if you move, lose coverage, or experience certain life changes. Changes made during this window take effect January 1 of the following year.

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

You must be a U.S. citizen or a permanent resident who has lived in the United States for at least five consecutive years to enroll in Medicare. If you are a permanent resident, you will need to provide proof of your status when you enroll. Non-citizens may have other coverage options depending on their visa status.

Do I have to enroll in Part A if I have employer coverage?

Yes. You must enroll in Part A (hospital insurance) when you turn 65, even if you have employer coverage. Part A has no premium for most people, so there is no financial reason to delay. You can delay Part B without penalty if your employer has 20 or more employees, but Part A enrollment is required.