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 have until the last day of the month you turn 65 to sign up without a penalty — in that June example, you can enroll through June 30.

The catch is that coverage does not start when ready. If you sign up during your initial enrollment period, Part A (hospital insurance) and Part B (medical insurance) coverage begins on the first day of the month you turn 65, regardless of when in that month you actually enroll. If you wait until later in your birth month to sign up, you still get coverage starting on the first of that month.

Missing this window costs you. If you do not sign up by the end of the month you turn 65, you face a permanent 10 percent increase to your Part B premium for each full 12-month period you go without coverage. That penalty stays with you for life, even if you sign up years later.

Key Takeaways

  • Your initial enrollment period opens three months before you turn 65 and closes at the end of the month you turn 65.
  • Part A and Part B coverage starts on the first day of the month you turn 65, even if you sign up late in that month.
  • Signing up after your initial period ends triggers a permanent 10 percent premium penalty for Part B that lasts your entire life.
  • If you are still working and have health insurance through your employer, you may be able to delay enrollment without penalty under specific conditions.
  • You sign up through Medicare.gov, by phone at 1-800-MEDICARE, or in person at your local Social Security office.

What happens if you are still working at 65

If you have health insurance through your current employer or your spouse's employer, you do not have to sign up for Medicare at 65. You can delay Part B enrollment without triggering the permanent penalty, but only if your employer coverage is based on current employment — not retiree coverage.

You must sign up for Part A (hospital insurance) at 65 even if you are working, because Part A has no premium for most people. Delaying Part A enrollment can result in a penalty if you later need it.

When you leave your job or lose employer coverage, you have eight months to sign up for Part B without penalty. This is called a Special Enrollment Period. If you miss this eight-month window, the permanent 10 percent penalty applies.

Early enrollment before age 65

You cannot sign up for regular Medicare before age 65 unless you have been receiving Social Security Disability Insurance (SSDI) for 24 consecutive months, or you have End-Stage Renal Disease (ESRD) or ALS (amyotrophic lateral sclerosis). These are the only circumstances under which Medicare coverage begins before age 65.

If you have been on SSDI for 24 months, Medicare Part A and Part B coverage begins automatically on the first day of the 25th month. You do not need to sign up; the enrollment happens without action on your part. You can decline Part B if you have other coverage, but you must do so actively.

People with ESRD can sign up for Medicare regardless of age. Those with ALS become may be able to access when ready upon diagnosis, without waiting periods. Both groups should contact Medicare directly to understand their specific enrollment timeline.

How to sign up during your enrollment period

You have three ways to enroll: online at Medicare.gov, by phone at 1-800-MEDICARE (1-800-633-4227), or in person at your local Social Security office. The online method is fastest — you can complete enrollment in about 10 minutes if you have your Social Security number and basic health information ready.

When you call, a representative walks you through the same questions: your name, date of birth, Social Security number, and whether you want Part A, Part B, or both. Part D (prescription drug coverage) is a separate enrollment, handled either at the same time or later. The phone line is open Monday through Friday, 8 a.m. to 7 p.m. Eastern time.

At a Social Security office, staff can help you enroll in person. Bring your Social Security card, proof of citizenship or legal residency, and proof of age. Wait times at offices vary widely; calling ahead to ask about current wait times can save you a trip.

Part D and Medigap enrollment timing

Part D (prescription drug coverage) has its own enrollment rules. You can sign up for Part D during your initial Medicare enrollment period, or during the annual open enrollment period from October 15 to December 7 each year. If you do not sign up when you first become may be able to access and you go without Part D coverage, you pay a permanent penalty when you eventually enroll — 1 percent of the national average Part D premium for each month you were without coverage.

Medigap (supplemental insurance) also has a special enrollment window. You have six months from the date you sign up for Medicare Part B to enroll in a Medigap plan without medical underwriting. After that window closes, insurers can deny you coverage or charge you more based on your health history. If you have employer retiree coverage, your Medigap window may be different; check with your plan administrator.

What to do if you missed your enrollment important date

If you did not sign up by the end of the month you turned 65, you can still enroll, but penalties explore. You pay the permanent 10 percent Part B premium increase for as long as you have Medicare. The only exception is if you had a may have access to life event — such as losing employer coverage, moving out of the country and returning, or a change in your immigration status — that triggers a Special Enrollment Period.

A Special Enrollment Period gives you two months from the date your may have access to event occurred to sign up without penalty. Losing employer coverage is the most common may have access to event. You must document the reason for your late enrollment when you sign up; Medicare will ask for proof such as a letter from your former employer stating when coverage ended.

Even with a penalty, signing up is still worth doing. Part B covers doctor visits, outpatient care, and preventive services. The longer you wait, the higher your cumulative penalty becomes, so enrolling as soon as you realize you missed the important date limits the damage.

Frequently Asked Questions

Can I sign up for Medicare before I turn 65 if I am not on disability?

No. The only exceptions are SSDI recipients who have been on the program for 24 months, people with ESRD, and people with ALS. Everyone else must wait until three months before their 65th birthday to enroll in regular Medicare.

What if I turn 65 in the middle of the month — does my coverage start mid-month?

No. Coverage always starts on the first day of the month you turn 65, regardless of what day in that month your birthday falls. If you turn 65 on June 15, your coverage begins June 1.

Do I have to sign up for Part B if I am still working and have employer insurance?

No, you can delay Part B without penalty if your employer coverage is based on current employment. You must still sign up for Part A at 65. When you leave your job, you have eight months to sign up for Part B without penalty.

What is the penalty for signing up late, and does it ever go away?

The Part B penalty is 10 percent of the national average premium for each full 12-month period you go without coverage. This penalty is permanent and stays on your bill for life, even if you move to a different state or change plans.

Can I change my mind after I sign up for Medicare?

Yes. You have until the end of the calendar year to make changes to your Part B, Part D, and Medigap coverage. Changes take effect January 1. Outside the annual open enrollment period, changes are limited to people with may have access to life events.