You are eligible for Medicare at age 65, but you may not need to sign up then.

The best time to enroll in Medicare depends on whether you or your spouse is still working and you have health insurance from that employer. If you make the wrong decision, you could end up with late enrollment penalties and coverage gaps.

Who is automatically enrolled in Medicare?

If you’re already receiving Social Security or Railroad Retirement Board benefits at least four months before your 65th birthday, you’ll be enrolled automatically in Medicare Part A and Part B. If you live in Puerto Rico and are receiving those benefits, only Part A will come to you automatically; you’ll need to take extra steps to enroll in Part B.

You’ll receive your Medicare card in the mail and can start using it the beginning of the month you turn 65. If your birthday is on the first day of a month, your coverage will start a month earlier.

Part A, which covers hospitalization, is free if you or your spouse has paid Medicare taxes for 40 quarters, the equivalent of 10 years. Part B, which covers doctor and outpatient services, has a monthly premium of $170.10 for most people (high earners pay more) in 2022, and the Social Security Administration will automatically deduct the premium from your monthly benefit.

But if you or your spouse is still working and you have health insurance from that employer, you may not have to enroll in Part B yet. You can send back the card and enroll in Part B later. Follow the instructions on the back of the card to delay enrolling in Part B if you’re already receiving Social Security or Railroad Retirement benefits.

What if I’m not automatically enrolled in Medicare?

You will need to take steps to sign up for coverage.

Almost 40 years ago, Congress passed a law to gradually raise the full retirement age — the age at which you get 100 percent of your Social Security benefits. Before then, full retirement age was 65, the same age as Medicare eligibility for those not receiving Social Security disability benefits.

Because people today must be older than 65 to receive full Social Security benefits, most folks who turn 65 haven’t signed up for Social Security yet. So they won’t be enrolled automatically in Medicare.

Should I sign up during my initial enrollment period?

For most people, the answer is yes. They need to sign up for Medicare during their seven-month initial enrollment period (IEP), which starts three months before the month you turn age 65 and ends three months after your birthday month. If your 65th birthday is in June, your IEP begins March 1 and ends Sept. 30.

If your birthday falls on the first day of a month, the whole initial enrollment period moves forward one month. For example, if your birthday is June 1, your IEP begins Feb. 1 and ends Aug. 31.

If you or your spouse is still working and you have health insurance coverage from that active employer, you may be able to wait. But otherwise, you need to sign up for Medicare during your IEP to avoid late enrollment penalties and delayed coverage.

The phrase “active employer” is key. If you have other insurance that isn’t from your own or your spouse’s current employer, you will still need to sign up for Medicare during your initial enrollment period. You need to sign up during your IEP in all of these circumstances: If you have

  • COBRA health coverage that extends the insurance you or your spouse received from an employer while working
  • Health insurance that you bought yourself and no employer provided it
  • No health insurance
  • Retiree benefits from your own or a spouse’s former employer
  • Veterans benefits from the Department of Veterans Affairs (VA) health system but no insurance from a current employer

When would my Medicare coverage start?

If you enroll during the first three months of your IEP, your Medicare coverage begins on the first day of the month you turn 65 or the first day of the previous month if your birthday falls on the first day of a month.

If you sign up for Part B during the fourth month — your birthday month — coverage begins the first day of the following month.

If you don’t enroll in Part B until later, in the fifth, sixth or seventh month of the IEP, coverage will be delayed by two or three months. However, those rules change in 2023, when the coverage will take effect the next month when you enroll after your birthday month.

You can sign up for premium-free Part A any time after your IEP starts. Your coverage will take effect six months retroactively, but no earlier than the month you turn age 65.

The best way to sign up for Medicare during your initial enrollment period is online at the Social Security website.

Do I qualify for a Medicare special enrollment period?

Perhaps, if you or your spouse is still working and you have health insurance from that employer. The special enrollment period (SEP) allows you to sign up for Medicare Part B throughout the time you have coverage from your or your spouse’s employer and for up to eight months after the job or insurance ends, whichever occurs first.

If you enroll at any point during this time, your Medicare coverage will begin the first day of the following month. And you will not be liable for late penalties, no matter how old you are when you finally sign up.

Your decision also depends on the size of your employer and whether the employer’s plan is first in line to pay your medical bills or second.

Larger companies. If you or your spouse work for a company with 20 or more employees, you can delay signing up for Medicare until the employment ends or the coverage stops, whichever happens first. These large employers must offer you and your spouse the same benefits they offer younger employees and their spouses, which means that the employer’s coverage can continue to be your primary coverage and pay your medical bills first.

Many people enroll in Medicare Part A at 65 even though they have employer coverage, because it’s free if they or their spouse has paid 40 or more quarters of Medicare taxes. But they often delay signing up for Part B while they’re still working so they don’t have to pay premiums for both Medicare and the employer coverage.

However, if you want to continue contributing pretax dollars to a health savings account (HSA), you should wait to sign up even for Part A. You can’t contribute to an HSA after you enroll in Medicare.

Small businesses. If you or your spouse work for a company with fewer than 20 employees, Medicare generally becomes the primary coverage at age 65 and the employer’s coverage becomes secondary. That means Medicare pays your medical bills first and your company’s group plan pays only for services it covers but Medicare doesn’t.

In this case, you usually need to sign up for Medicare during your initial enrollment period to avoid big coverage gaps.

Living abroad. The rules and issues to consider can be different if you’re living outside the United States.

Keep in mind

Part C, Medicare Advantage. You also have the option to enroll in a private Medicare Advantage plan during your IEP after you sign up for Part A and Part B.

Part D prescription plans. The rules are different for prescription drug coverage. You can sign up for private Part D coverage during your initial enrollment period, but you aren’t required to enroll if you have other prescription drug coverage that is considered at least as good as the Medicare-approved plans.

This “creditable coverage” can be from a current employer, retiree coverage, Tricare or another source. You will not be liable for Part D late enrollment penalties if you sign up within 62 days of losing your other prescription coverage.

https://www.aarp.org/health/medicare-qa-tool/turning-65-when-to-apply-for-medicare/