Medicare enrollment opens at 65, but the exact timing depends on your birthday and work status

You become may be able to access for Medicare at age 65, but you cannot enroll whenever you want. Instead, Medicare has specific enrollment windows — periods when you can sign up without penalty. Missing your window can cost you permanently higher premiums, even if you enroll years later.

The main enrollment period runs from three months before your 65th birthday through three months after it — a seven-month window total. If your birthday is in March, for example, you can enroll starting in December and through June. You do not have to wait until you turn 65 to sign up; you can start the month you turn 65.

If you are still working and covered by your employer's health plan, you may have a different timeline. People who delay Medicare because of active employer coverage can enroll without penalty during an eight-month Special Enrollment Period that begins the month your employment or coverage ends.

Key Takeaways

  • You can enroll in Medicare starting three months before your 65th birthday and have until three months after to sign up without penalty.
  • If you miss your initial enrollment window, you will pay a permanent 10 percent penalty on Part B premiums for as long as you have Medicare.
  • People still covered by an employer plan at 65 can delay enrollment and use an eight-month Special Enrollment Period after their coverage ends.
  • You must actively enroll in Medicare Parts A and B; they do not happen automatically even after you turn 65.
  • Spouses, survivors, and people on disability have different enrollment rules and may be able to enroll before age 65.

The Initial Enrollment Period: Your seven-month window at 65

Your Initial Enrollment Period is the only time you can enroll in Medicare without facing a permanent penalty. It runs for seven months: three months before the month you turn 65, the month you turn 65, and three months after.

You can enroll online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. The Social Security Administration handles Medicare enrollment, not your doctor or insurance company. If you enroll before you turn 65, your coverage will start the month you turn 65.

If you enroll during the month you turn 65 or after, your coverage start date depends on when in the month you enroll. Enrolling on the first of the month means coverage starts that month; enrolling on the 15th or later usually means coverage starts the following month. Check the exact date when you enroll.

What happens if you miss your enrollment window

If you do not enroll during your Initial Enrollment Period and you do not have a valid reason for the delay, you will pay a permanent 10 percent penalty on your Part B premium. This penalty stays with you for life, even if you enroll years later. A person who waits until age 70 to enroll will pay roughly 50 percent more than someone who enrolled at 65.

The same penalty applies to Part D (prescription drug coverage) if you go without it. The penalty is 1 percent of the national base premium for each month you were not enrolled, and it also stays permanent.

You can still enroll after your window closes, but only during the General Enrollment Period, which runs January 1 through March 31 each year. Coverage under this route starts July 1. This is a much slower path and carries the penalty, so it should only be your option if you truly cannot enroll during your Initial Enrollment Period.

Delaying enrollment if you have employer coverage

If you are still working at 65 and your employer offers health insurance, you may not need Medicare right away. Federal law allows you to delay Medicare without penalty if you are covered by an active employer plan — meaning your employer has 20 or more employees and you are actively working there or are a spouse of someone who is.

When your employment ends or your employer coverage stops, you have eight months to enroll in Medicare without penalty. This is your Special Enrollment Period, and it is separate from your Initial Enrollment Period. You must enroll within this eight-month window or face the permanent penalty.

Tell Medicare about your employer coverage when you enroll. You will need the name of your employer and the date your coverage ended. If you do not report this information and you miss your important date, you cannot go back and claim you had a valid reason for the delay.

People who can enroll before age 65

You do not have to be 65 to get Medicare if you have been receiving Social Security Disability Insurance (SSDI) for 24 months. Once you have been on disability for two years, you become may be able to access for Medicare regardless of age. You will be automatically enrolled, but you should confirm your enrollment by checking your Social Security account online or calling Social Security.

People with End-Stage Renal Disease (ESRD) — permanent kidney failure requiring dialysis or transplant — can enroll in Medicare at any age. You have a three-month enrollment window: the month you start dialysis or the month of your transplant, plus one month before and one month after.

Spouses and ex-spouses of people receiving Social Security can sometimes enroll in Medicare at 62 if their spouse is 62 or older, but the rules are complex and depend on your work history. Contact Social Security directly to understand your specific situation.

How to enroll and what you will need

You can enroll through three routes: 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 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 or your pharmacy information so you can compare plans. You do not need to choose a specific plan during enrollment; Medicare will assign you a default plan if you do not pick one, though you can change it during the annual open enrollment period in the fall.

If you enroll online, you will receive a confirmation number when ready. Keep this number. Your Medicare card will arrive in the mail within two to four weeks. If you need coverage to start sooner, enroll by phone or in person so you can get a temporary proof of coverage right away.

Annual changes and re-enrollment after your first year

After your first year on Medicare, you do not re-enroll. Your coverage continues automatically. However, you can change your plans during the Annual Enrollment Period (AEP), which runs October 15 through December 7 each year. During this time, you can switch between Original Medicare and Medicare Advantage, change your prescription drug plan, or add or drop supplemental coverage.

If you do not change anything during AEP, your current plans continue into the next year. Changes you make during AEP take effect January 1. If you miss AEP and want to change plans, you will have to wait until the next October, unless you have a may have access to life event like moving to a new state or losing employer coverage.

Frequently Asked Questions

Can I enroll in Medicare before I turn 65?

You can enroll starting three months before your 65th birthday, so if you turn 65 in June, you can enroll in March. If you are on disability and have been receiving SSDI for 24 months, you can enroll at any age. People with end-stage renal disease can also enroll before 65.

What is the penalty for enrolling late?

You will pay a permanent 10 percent increase on your Part B premium for each year you were not enrolled. For Part D, the penalty is 1 percent of the national base premium per month of non-enrollment. Both penalties stay with you for life, even if you enroll years later.

Do I automatically get Medicare when I turn 65?

No. If you are already receiving Social Security, you will be automatically enrolled in Parts A and B about three months before you turn 65. If you are not yet receiving Social Security, you must actively enroll through Medicare.gov, by phone, or at a Social Security office.

What if my birthday is in a month with fewer days?

Your enrollment period is based on the calendar month, not the number of days. If your birthday is February 15, your three-month-before window starts November 1, regardless of how many days are in November or February.

Can I change my mind after I enroll?

Yes, but only during specific windows. You have until the end of the year to make changes to your initial enrollment. After that, you can change plans only during the Annual Enrollment Period in October and November, or if you have a may have access to life event.