Medicare Enrollment

You can only enroll in Medicare at certain times. The window opens three months before your 65th birthday month and ends three months after it. You can sign up online, by phone or in person at your Social Security office. Enrollment is automatic if you’re already receiving Social Security benefits.

You can apply for Medicare even if you are not planning to retire right away.

Medicare enrollment takes less than 10 minutes online, according to the Social Security Administration. The agency processes applications for Medicare.

Financial expert John Clark explains Medicare eligibility and the three ways to sign up for coverage.

Initial Enrollment Periods for Medicare

Your initial enrollment period runs seven months. It begins three months before your 65th birthday month. It includes your birthday month and the next three months after it.

This is when you can first sign up for Medicare.

You enroll in Medicare through the Social Security Administration. After that, your benefits will be administered by the U.S. Centers for Medicare & Medicaid Services.

How to Enroll in Medicare
  • You can apply online at the Social Security website.
  • Call the Social Security Administration toll-free at 1-800-772-1213 (TTY 1-800-325-0778).
  • Visit your local Social Security office. The agency has a Social Security office locator at its website.

When you first enroll, you will sign up for Medicare Part A hospital insurance. If you’ve worked and paid Medicare payroll taxes for at least 10 years, there will be no premium. You’ll be given a choice of signing up for Medicare Part B medical insurance, which covers things such as doctor visits and outpatient services.

You’ll also be able to sign up for a Medicare Advantage plan, sometimes called Medicare Part C. It helps cover out-of-pocket expenses such as copayments, coinsurance and deductibles. If you stay with Original Medicare, you’ll be able to select stand-alone prescription drug coverage through a Medicare Part D plan. Otherwise, Medicare Part D is often included in a Medicare Advantage plan.

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Open Enrollment Periods for Medicare

Outside of the initial enrollment period, there are certain times each year when you can change between or enroll in different Medicare plans. These are part of Medicare open enrollment.

Did you know?
The Medicare open enrollment period runs from Oct. 15 to Dec. 7 each year.

Open enrollment is available because Medicare health and drug plans can make changes once a year. Changes may include how much the plans cost, what they cover and what doctors, pharmacies and other health care providers are in their networks.

Medicare open enrollment gives you a chance to change to a new plan if you don’t like those changes.

Special Enrollment Periods for Medicare

Medicare Special Enrollment Periods can happen any time during the year due to changes in your circumstances.

When Medicare Special Enrollment Is Allowed
  • When you move somewhere outside of the coverage area of your Medicare Advantage plan.
  • When you leave your employer’s health insurance plan.
  • When Medicare ends its contract with your Medicare Advantage provider.

Late Enrollment Penalties

When you first enroll in Medicare, you can sign up for Medicare Part A hospital insurance and Medicare Part B medical insurance. If you qualify for Medicare and have paid payroll taxes into the system for at least 10 years, there should be no premium for Part A.

Because you have to pay a premium for Part B, you can decline it. But applying for it later will cost you a monthly penalty. The cost of your Part B monthly premium will increase by 10 percent for each 12-month period you were eligible but did not enroll.

You may also have to pay a late enrollment penalty on Medicare Part D if you go more than 63 days without creditable prescription drug coverage after your initial enrollment period ends. You’ll have to pay this higher monthly premium for as long as you have Medicare prescription drug coverage.

There is no late enrollment penalty fee for Medicare Advantage plans.

Frequently Asked Questions About Medicare Enrollment

Medicare is a complex health insurance system, and it can be hard to grasp all of its intricacies without studying how different parts work. Don’t be intimidated about asking questions with someone who may be able to explain something you don’t understand about it.

Tom Parkin, Senior Marketing Consultant at Senior Market Sales, explains how to prepare before enrolling in Medicare.

Keep in mind that some of the most frequently asked questions are some of the most basic.

Is Medicare enrollment automatic at age 65?
Medicare enrollment is automatic only if you are already receiving Social Security benefits. If you have not received Social Security benefits, you must enroll for Medicare online, by phone or in person at your local Social Security office.
Do I have to sign up for Medicare when I turn 65?

If you have health insurance through your or your spouse’s employer, you may not have to enroll in Medicare when you turn 65.

If the employer has 20 or more employees, you can delay enrolling in Medicare until your employer’s health coverage ends without any penalties. Then you will have a special enrollment period to sign up for Medicare.

If the employer has fewer than 20 employees, the company can require you to enroll in Medicare instead of using the company’s health insurance.

What happens if I miss my Medicare enrollment?
If you miss your initial or special enrollment periods, you can still enroll in Medicare during the next open enrollment period. But you may incur additional monthly penalties added to your Medicare Part B and Part D premiums.
When will I get my Medicare card?

If you actively enroll, you will get your Medicare card about three weeks after you sign up.

If you are already receiving Social Security benefits before you turn 65, you’ll be automatically enrolled, and your Medicare card should show up a couple of months before your 65th birthday.

When is the Medicare open enrollment period?
The Medicare open enrollment period is Oct. 15 to Dec. 7, each year. You will be able to enroll in Medicare coverage for during that time, if you don't enroll during your initial or special enrollment period.
Last Modified: November 10, 2021

5 Cited Research Articles

  1. U.S. Centers for Medicare & Medicaid Services. (2020, February 11). Top 5 Things You Need to Know About Medicare Enrollment. Retrieved from
  2. U.S. Centers for Medicare & Medicaid Services. (2020, February 11). Medicare Open Enrollment.
  3. U.S. Social Security Administration. (2019, September). Understanding Medicare Advantage and Prescription Drug Plan Enrollment Periods. Retrieved from
  4. U.S. Centers for Medicare & Medicaid Services. (n.d.). Get Started with Medicare. Retrieved from
  5. U.S. Social Security Administration. (n.d.). Apply for Social Security Benefits. Retrieved from