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 the month you turn 65. You do not have to wait until your birthday arrives — you can sign up starting three months before the month you turn 65. For example, if your birthday is in June, you can sign up beginning in March. The window to sign up without penalty closes three months after the month you turn 65, so in that same example, you would have until September to enroll without extra costs.

If you are already receiving Social Security benefits when you turn 65, Medicare enrollment happens automatically — you do not need to do anything. If you are not yet taking Social Security, you must sign up for Medicare yourself during your enrollment window, even if you plan to delay Social Security. Missing this window can result in permanent premium increases on your Part B and Part D coverage.

Some people become may be able to access before 65. If you have received Social Security Disability Insurance (SSDI) for 24 months, or if you have end-stage renal disease or ALS, you may be able to enroll in Medicare earlier. The rules for these situations differ, so contact Social Security directly to learn whether you may have access to.

Key Takeaways

  • You can sign up for Medicare starting three months before the month you turn 65, and you have until three months after that month to enroll without penalty.
  • If you receive Social Security benefits, Medicare enrollment is automatic at 65 and requires no action on your part.
  • If you do not receive Social Security, you must sign up for Medicare yourself during your enrollment window or face permanent premium increases.
  • Certain conditions — including 24 months on disability or end-stage renal disease — may allow you to enroll in Medicare before age 65.
  • Your enrollment window is seven months long: three months before, the month you turn 65, and three months after.

How to sign up during your initial enrollment period

You have three ways to sign up: online through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office. Online enrollment through Medicare.gov is usually the fastest option and takes about 10 minutes. You will need your Social Security number, date of birth, and information about your current health coverage if you have it.

By phone, a representative can walk you through the process and answer questions about which parts of Medicare you need. Social Security offices can also help, though wait times vary by location. If you are already receiving Social Security, you may receive a notice in the mail a few months before your 65th birthday with instructions to confirm your Medicare enrollment online.

What happens if you miss your enrollment window

If you do not sign up during your initial seven-month window, you enter a period called the General Enrollment Period, which runs January 1 through March 31 each year. You can sign up during this time, but your coverage will not start until July 1 of that year — a delay of several months depending on when you enroll.

More importantly, you will owe a late enrollment penalty on Part B and Part D for as long as you have Medicare. The penalty is a percentage of the standard premium, calculated for each month you were may be able to access but not enrolled. This penalty does not go away — it stays on your bill permanently, even if you move to a different plan later. The only exception is if you had creditable coverage (health insurance that meets Medicare's standards) during the time you were not enrolled.

Special enrollment periods for life changes

If you experience certain life events — such as losing employer health coverage, moving to a different state, or getting married — you may be able to sign up for Medicare outside your initial enrollment window without penalty. These are called Special Enrollment Periods, and they typically last two months from the date of the may have access to event.

may have access to events include losing group health coverage through an employer, moving out of your plan's service area, or becoming a U.S. citizen or permanent resident. You must report the event to Medicare and provide documentation — such as a letter from your employer stating when coverage ended. Contact Medicare at 1-800-MEDICARE to report a may have access to event and learn whether you are may be able to access for a Special Enrollment Period.

Enrollment if you are still working at 65

If you are still employed and covered by your employer's health plan at 65, you may be able to delay Medicare Part B without penalty. This is called creditable coverage. Your employer's plan must meet Medicare's standards, which most large employer plans do. You can continue on your employer plan and sign up for Medicare later without the late enrollment penalty, as long as you enroll within eight months of leaving your job or losing the coverage.

However, you should still sign up for Part A (hospital insurance) at 65 even if you delay Part B, because Part A is usually free and has no penalty for late enrollment. Part D (prescription drug coverage) does carry a penalty if delayed, so if your employer plan does not cover prescriptions as well as Medicare Part D would, you may want to enroll in Part D at 65 to avoid the penalty.

Medicare Advantage and Medigap enrollment timing

Once you are enrolled in Medicare Parts A and B, you can choose between Original Medicare (Parts A and B with a separate Medigap or Part D plan) or Medicare Advantage (an all-in-one alternative). Your Initial Coverage Election Period — the same seven-month window when you sign up for Parts A and B — is also when you can enroll in Medicare Advantage or Medigap without medical underwriting.

If you enroll in Original Medicare first and later want to switch to Medicare Advantage, or vice versa, you have limited windows to do so. The Annual Enrollment Period runs October 15 through December 7 each year, and any changes take effect January 1. If you miss this window, you may not be able to change plans until the next year, with limited exceptions for people who may have access to for Special Enrollment Periods.

Frequently Asked Questions

Can I sign up for Medicare before I turn 65?

You can sign up starting three months before the month you turn 65. If you have received SSDI for 24 months, have end-stage renal disease, or have ALS, you may be able to enroll earlier. Contact Social Security at 1-800-772-1213 to learn whether you may have access to for early enrollment.

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

You must be a U.S. citizen or permanent resident to enroll in Medicare. If you are a permanent resident, you can sign up at 65 just like a citizen. If you are not yet a permanent resident, you cannot enroll until you become one.

Do I have to sign up for all parts of Medicare at once?

No. You must enroll in Part A (hospital insurance), but you can delay Part B (medical insurance) if you have creditable employer coverage. Part D (prescription drugs) and Medigap or Medicare Advantage are separate choices you make after Part A and B are active.

What if I was not automatically enrolled in Medicare?

If you were not receiving Social Security at 65, you were not automatically enrolled. You must sign up yourself through Medicare.gov, by calling 1-800-MEDICARE, or at your local Social Security office. Do this during your seven-month enrollment window to avoid late penalties.

Can I change my Medicare plan after I enroll?

Yes, during the Annual Enrollment Period from October 15 through December 7 each year. Changes take effect January 1. Outside this window, you can only change plans if you may have access to for a Special Enrollment Period due to a life event or loss of coverage.