You can sign up for Medicare starting three months before the month you turn 65

Medicare enrollment opens on the first day of the month that is three months before your 65th birthday. If you turn 65 in June, your enrollment window opens on March 1. You can sign up anytime during that three-month window, and your coverage will begin on the first day of the month you turn 65.

The enrollment period lasts until three months after the month you turn 65. Using the June example again, your window closes on September 30. If you miss this window, you can still sign up later, but you may face a permanent penalty on your premiums — the longer you wait after 65, the higher the penalty climbs.

If you are already receiving Social Security benefits before age 65, Medicare will contact you automatically about three months before your 65th birthday. You do not have to do anything unless you want to change your coverage choices. If you are not yet receiving Social Security, you will need to contact Medicare yourself to sign up.

Key Takeaways

  • Your initial enrollment period begins three months before you turn 65 and ends three months after, giving you a seven-month window to sign up without penalty.
  • If you are receiving Social Security, Medicare will reach out to you automatically; if not, you must contact Medicare to enroll.
  • Signing up late after age 65 triggers a permanent premium penalty that increases the longer you delay, so timing matters even if you do not need coverage right away.
  • You can sign up online at Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.
  • If you are still working and covered by your employer's health plan, you may be able to delay Part B enrollment without penalty, but you must report this to Medicare.

What happens if you miss the initial enrollment window

If you do not sign up during your seven-month initial period, you enter what Medicare calls the General Enrollment Period, which runs from January 1 to March 31 each year. You can sign up during any General Enrollment Period, but your coverage will not start until July 1 of that year — meaning a gap in coverage if you sign up in January.

More importantly, you will owe a late enrollment penalty on Part B (medical insurance) and Part D (prescription drug coverage) for as long as you have Medicare. The penalty is calculated as a percentage of the standard premium and compounds each year you go without coverage. For example, if you wait two years past 65 to sign up for Part B, your penalty will be roughly 20 percent of the current Part B premium, added to your monthly bill permanently.

There are narrow exceptions to this penalty. If you were covered by an employer health plan while you or your spouse was still working, you may have had creditable coverage that delays the penalty clock. You must report this coverage to Medicare when you sign up, and you will need documentation from your employer showing the dates you were covered.

Special enrollment periods for life changes

If you experience certain life events — losing employer coverage, moving to a different state, getting married or divorced — you may open a Special Enrollment Period outside the normal windows. These periods typically last two months and let you sign up without the late penalty, even if you are past 65.

Common may have access to events include losing health coverage through your employer, losing coverage through a family member's employer, moving out of your current plan's service area, or becoming a U.S. citizen or permanent resident. You will need to document the event — a termination letter from your employer, a divorce decree, or proof of residency, depending on what changed.

Contact Medicare directly to report a life change and confirm whether you may have access to for a Special Enrollment Period. Do not assume your situation qualifies; the rules are specific, and reporting the wrong event can delay your enrollment.

Signing up before you turn 65

You can begin the sign-up process up to three months before your birthday. Most people sign up online at Medicare.gov, where you can create an account and complete the enrollment in about 15 minutes. You will need your Social Security number, date of birth, and citizenship or permanent resident status.

If you prefer to sign up by phone, call 1-800-MEDICARE (1-800-633-4227). Representatives are available Monday through Friday, 8 a.m. to 8 p.m. Eastern time, and on weekends during certain months. Have your Social Security number and birth date ready when you call.

You can also visit your local Social Security office in person to enroll. Bring your Social Security card, proof of citizenship or permanent residency, and proof of age. No appointment is required, though wait times vary by location.

Deciding between Original Medicare and Medicare Advantage

When you sign up, you will choose between Original Medicare (Part A and Part B) or a Medicare Advantage plan (Part C). Original Medicare is run by the federal government and covers hospital stays, doctor visits, and some preventive care. Medicare Advantage is offered by private insurance companies and typically includes prescription drug coverage and extra benefits like dental or vision, but usually requires you to use doctors in a specific network.

You do not have to decide when ready. If you enroll in Original Medicare during your initial period, you can switch to a Medicare Advantage plan during the annual enrollment period (October 15 to December 7 each year) without penalty. However, if you choose a Medicare Advantage plan first and later want to switch back to Original Medicare, you may face restrictions and higher costs.

If you choose Original Medicare, you will also need to decide whether to add Part D (prescription drug coverage) and Medigap (supplemental insurance that covers costs Original Medicare does not). These decisions should be made during your initial enrollment period to avoid late penalties.

Reporting employer coverage to avoid penalties

If you are still working and covered by your employer's health plan at age 65, you may be able to delay Part B enrollment without penalty. This is called creditable coverage. However, you must still enroll in Part A (hospital insurance) at 65, and you must tell Medicare that you have employer coverage.

When you do sign up for Part B later — usually within eight months of leaving your job or losing coverage — you will not owe a late penalty if you report the creditable coverage. Without this documentation, Medicare will assume you delayed enrollment and charge you the penalty.

Contact Medicare before you turn 65 to report your employer coverage. You will need your employer's group health plan name, the dates you have been covered, and confirmation that the plan meets Medicare's standards for creditable coverage. Your employer's benefits department can provide this information.

Frequently Asked Questions

What if I turn 65 and I am still working?

You can delay Part B enrollment if your employer has 20 or more employees and you are covered by the company health plan. You must still enroll in Part A at 65. Report your employer coverage to Medicare to avoid a late penalty when you eventually sign up for Part B.

Can I sign up for Medicare before I turn 65?

No, unless you have been receiving Social Security Disability Insurance (SSDI) for 24 months or have end-stage renal disease or ALS. Otherwise, your enrollment window opens three months before your 65th birthday.

What if I miss my enrollment important date by a few days?

If you miss the important date, you enter the General Enrollment Period (January 1 to March 31), and your coverage will not start until July 1. You will also owe a late penalty. Contact Medicare when ready to understand your options and confirm the exact important date you missed.

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 if you have creditable employer coverage. Part D and Medigap are optional but should be added during your initial enrollment period to avoid penalties.

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

You must be a U.S. citizen or permanent resident to enroll in Medicare. Permanent residents must have lived in the United States for at least five consecutive years. Contact Medicare to confirm your may be able to access based on your immigration status.