Turning 65 Soon? Here’s When You Should Sign Up for Medicare

Whether you’re working or retired, pay attention to this birthday. You’ll have some decisions to make

5-minute read

Article 5 out of 15 in Medicare Basics

Kimberly Lankford,

Updated November 09, 2026

AARP

Reviewed by

Harriet Komisar, Ph.D

Updated November 09, 2026

An illustrated slice of birthday cake with lit candles shaped like the number 65, being served on a cake spatula.

Chris Gash

Key takeaways

Best time to enroll in Medicare differs for each person.
Age 65 opens the door to Medicare for most people.
Delaying may be possible if your spouse, you still work.
On Social Security? You may be enrolled automatically.
After signing up, you’ll have more decisions to make.

Age 65 is the earliest most people are eligible for Medicare unless they qualify sooner because of a disability.

But the best time for you to enroll depends on two main factors. Do you:

Still work, or does your spouse?
Collect Social Security if you’re retired?

Your answers to these questions will put you on different paths as you turn 65.

Medicare is a bit of a smorgasbord. You can get everything all at once, you can enroll only in premium-free Part A for hospital services if you or your spouse paid Medicare taxes for 40 quarters or you can decide not to sign up at all at age 65.

But Medicare does have some confusing rules that can lead to late enrollment penalties — some for life. And those rules could lead to coverage gaps that might leave you with thousands of dollars in medical bills if you don’t pay attention to the details.

Age 65 is when your enrollment window opens

Your 65th birthday is important for Medicare because your seven-month initial enrollment period is built around it, three months on either side of your birthday month. If your birthday falls on the first day of a month, the whole initial enrollment period shifts one month earlier — consider it a quirk of Medicare.

If you sign up immediately when your initial enrollment period begins, your Medicare coverage won’t start until your birthday month unless you were born on the first of a month. Then it starts the month before your birthday month.

If you sign up in your birthday month or later, Medicare will cover you starting the next month. Missing your initial enrollment period altogether may mean you have to wait to enroll unless you qualify for a special enrollment period later.

If you’re still working, you may be able to delay

In part because Social Security’s full retirement age is 67 for everyone turning 65 today, more and more people have a job. And many of them have health insurance that they may want to keep because of its costs, benefits or family coverage.

If either your spouse or you still work and you have medical insurance from that employer — not a previous place where you’ve qualified for COBRA coverage or a retiree plan — you may be able to wait. Then you’ll be able to sign up for Medicare without penalty after the employment ends or coverage stops, whichever happens first.

The rules change at 65, important for people who qualify for Medicare earlier because of a disability.

The key here is whether your company’s insurance will pay first, what insurers call a primary payer, or is second in line after Medicare. Insurance at companies with 20 or more employees, what Medicare considers large employers, is primary.

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With 10 years of work or longer through you or your spouse, you qualify for premium-free Part A. Many people sign up because it can act as a secondary payer for some hospital expenses that your employer’s insurance doesn’t cover.

If your company’s insurance is a high-deductible health plan and you want to continue contributing to your health savings account (HSA), you should hold off on signing up for any part of Medicare. Otherwise, you could face tax penalties.

Businesses with fewer than 20 on staff are what Medicare considers small. In most cases, Medicare becomes the primary payer, even if you haven’t signed up yet, and the work plan pays second, which can be a problem that lands in your wallet if you have medical needs that had been covered through your employer’s insurance when you were younger.

If your health insurance is coming through a small company, you won’t want to delay signing up for Medicare. This is the time to check with your employer for the bottom line.

On Social Security now? You’re probably enrolled automatically

If you’re already receiving Social Security or Railroad Retirement Board (RRB) 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.

Automatic doesn’t mean complete. You’ll still need to make some decisions after you receive your Medicare number, just like those who must make an effort to sign up.You also may find that you qualify for some financial assistance, potentially a Medicare Savings Program for Part B premiums and maybe Part A premiums and Extra Help for Part D premiums.

After you get your Medicare card, you have more to do

No matter when or how you’ve enrolled, your work isn’t complete when you receive your Medicare card. After you get both Part A and Part B, you’ll need to choose between original Medicare and Medicare Advantage.

With original Medicare, the federal health insurance program that combines Part A hospitalization and Part B provider services, you’ll want to consider adding separate plans for prescription drugs and out-of-pocket costs, and you’ll need to check your Part D plan every year Oct. 15 to Dec. 7 during open enrollment to make sure your medications are still covered and your costs are within budget.

If you choose Medicare Advantage, the private insurers’ alternative to original Medicare, you’ll need to analyze available medical providers, medication lists and your costs before selecting a plan. And you’ll have to review these options each year or risk coverage changes or discontinued services.

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If you’re going with only Part A for now because your employer has a health plan you like and drug coverage that’s as good or better than Part D for prescriptions, you can wait on these decisions until you sign up for Part B when you retire or otherwise lose priv you’re allowed to sign up

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This story, originally published July 25, 2022, has been updated to focus on actions that need to be taken at age 65.

About the author

Kimberly Lankford is a contributing writer who covers Medicare and personal finance and writes about insurance for The Wall Street Journal | Buy Side. She wrote about insurance, Medicare, retirement and taxes for more than 20 years at Kiplinger Personal Finance and has written for The Washington Post and The Boston Globe. She received the personal finance Best in Business award from the Society of American Business Editors and Writers and the New York State Society of Certified Public Accountants’ excellence in financial journalism award for her guide to Medicare.

About the reviewer

Harriet Komisar, a senior strategic policy adviser for health security at the AARP Public Policy Institute, previously worked as a research professor at Georgetown University’s Health Policy Institute and what is now the McCourt School of Public Policy, a visiting policy analyst at the federal Department of Health and Human Services and a principal analyst at the Congressional Budget Office. She earned her doctorate in economics from Cornell University.