You're about to turn 65, and everyone keeps asking whether you've signed up for Medicare yet. If you've been collecting Social Security for at least four months by the time you turn 65, here's the good news: you don't have to sign up at all. You're enrolled automatically, and your card shows up in the mail before your coverage starts.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare If you're not drawing Social Security yet, though, the job is yours, and missing the window can cost you.
In This Guide
- Key Takeaways
- Are You Automatically Enrolled in Medicare at 65?
- Part B Is Added Automatically Too, But You Can Turn It Down
- Who Isn't Automatically Enrolled in Medicare
- Frequently Asked Questions
- Learn More
Are You Automatically Enrolled in Medicare at 65?
So here's the short version for anyone already getting a Social Security check: yes, you're enrolled, and you don't lift a finger for Part A. Federal law says that once you've turned 65 and you're entitled to monthly Social Security or railroad retirement benefits, you're entitled to Medicare Part A, the hospital-insurance side of Medicare. The regulation puts you among the people who need not file an application for hospital insurance, so enrollment is automatic.Office of the Law Revision Counsel, U.S. House of Representatives. (n.d.). 42 U.S.C. 426 — Entitlement to hospital insurance benefits (Office of the Law Revision Counsel, uscode.house.gov). uscode.house.gov. Retrieved Jul 13, 2026, from https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title42-section426&num=0&edition=prelim
The same goes if your monthly benefit comes from the Railroad Retirement Board (RRB) instead of Social Security, according to Medicare's sign-up guidance. Either way, the government already has what it needs, so it enrolls you and mails you a card.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare
There's a timing condition worth knowing, though, and it's the one that trips people who claim Social Security late. Medicare sets up that automatic enrollment for people whose Social Security or RRB benefits started at least four months before they turn 65. Start your benefits a month or two before your birthday and the automatic path doesn't apply to you: signing up is back in your hands, on the same schedule as everyone who isn't collecting yet.Centers for Medicare & Medicaid Services. (n.d.). Open Enrollment. medicare.gov. Retrieved Sep 2, 2026, from https://www.medicare.gov/health-drug-plans/open-enrollment
That card is the thing to watch for. Medicare says your red-white-and-blue card shows up in the mail about three months before your coverage starts.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare For most people that coverage begins on the first day of the month they turn 65, since premium-free Part A starts the month you turn 65 no matter when you signed up.Centers for Medicare & Medicaid Services. (n.d.). Open Enrollment. medicare.gov. Retrieved Sep 2, 2026, from https://www.medicare.gov/health-drug-plans/open-enrollment If the card doesn't arrive, that's your signal to call Social Security, not a sign that something's wrong with your enrollment.
Part B Is Added Automatically Too, But You Can Turn It Down
Part B, the medical-insurance side that covers doctor visits and outpatient care, works the same way if your Social Security benefits started in time: Medicare's guidance says it's added automatically, and you don't apply for it separately either. One place that's different is Puerto Rico, where people who qualify for automatic enrollment get Part A only and have to sign up for Part B themselves.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare
Here's the wrinkle. Part A is premium-free for almost everyone, but Part B isn't. Most people pay the standard Medicare Part B premium, $202.90 a month in 2026, and it comes straight out of your Social Security check.Centers for Medicare & Medicaid Services. (2026). 2026 Medicare Parts A & B Premiums and Deductibles. cms.gov. Retrieved Aug 7, 2026, from https://www.cms.gov/newsroom/fact-sheets/2026-medicare-parts-b-premiums-deductibles
That's why Medicare lets you turn Part B down. If you're still working past 65 with solid health coverage through your job, or you're covered under a spouse's active employer plan, you may not want to start paying for Part B yet. Your Medicare package arrives with instructions for keeping Part B or refusing it, and the deadline to decide is printed right there. One caution before you send anything back: turning down Part B without job-based coverage that lets you delay can trigger a late-enrollment penalty of 10% of the premium for each full 12-month period you could have had Part B, for as long as you have Part B.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare If you're not sure your other coverage counts, ask before you decline. And if you do delay, watch the clock on the way back in. The Special Enrollment Period that lets you pick up Part B later without a penalty ends eight months after the group health plan coverage or the employment ends, whichever happens first. COBRA and retiree coverage aren't coverage based on current employment, so when one of those runs out it opens no Part B Special Enrollment Period, and waiting past that point costs you the penalty for life.Centers for Medicare & Medicaid Services. (n.d.). Open Enrollment. medicare.gov. Retrieved Sep 2, 2026, from https://www.medicare.gov/health-drug-plans/open-enrollment
Who Isn't Automatically Enrolled in Medicare
Now the other side, and it's the one that catches people. A lot of folks aren't collecting Social Security the day they turn 65. Full retirement age is 67 for anyone born in 1960 or later, which covers everyone turning 65 now, so plenty of people keep working and wait to claim.U.S. Government Publishing Office. (n.d.). 20 CFR 404.409 — What is full retirement age? (Social Security Administration, eCFR). ecfr.gov. Retrieved Sep 4, 2026, from https://www.ecfr.gov/current/title-20/chapter-III/part-404/subpart-D/section-404.409 If that's you, Medicare's sign-up guidance is blunt about it: there's no automatic enrollment, nobody mails you a card, and signing up is on you.Centers for Medicare & Medicaid Services. (n.d.). Open Enrollment. medicare.gov. Retrieved Sep 2, 2026, from https://www.medicare.gov/health-drug-plans/open-enrollment
You do it through Social Security, which runs Medicare enrollment even though Medicare is a separate program. You can apply online at ssa.gov or by phone, and the window to do it is your Initial Enrollment Period, the roughly seven-month stretch around your 65th birthday.Centers for Medicare & Medicaid Services. (n.d.). Open Enrollment. medicare.gov. Retrieved Sep 2, 2026, from https://www.medicare.gov/health-drug-plans/open-enrollment Our guides on when to sign up and how to actually do it walk through the timing and the steps.
Miss that window without job-based coverage that lets you delay, and the penalty lands on Part B: 10% of the premium for each full 12-month period you could have had Part B and didn't, for as long as you have Part B.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare So if you're turning 65 and you're not already on Social Security, don't assume it's handled. It isn't.
What that penalty does not do is take Part A away from you, and this is the part people get told wrong. Hospital insurance is governed by its own regulation, and that regulation is written the other way around. Someone who reaches 65 without having claimed Social Security files an application for Part A: filing is the route to it, not a forfeiture of it.Office of the Law Revision Counsel, U.S. House of Representatives. (n.d.). 42 U.S.C. 426 — Entitlement to hospital insurance benefits (Office of the Law Revision Counsel, uscode.house.gov). uscode.house.gov. Retrieved Jul 13, 2026, from https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title42-section426&num=0&edition=prelim And if you establish entitlement to Social Security or railroad retirement benefits at any time after you turn 65, you land right back in the group that need not file an application for hospital insurance at all.Office of the Law Revision Counsel, U.S. House of Representatives. (n.d.). 42 U.S.C. 426 — Entitlement to hospital insurance benefits (Office of the Law Revision Counsel, uscode.house.gov). uscode.house.gov. Retrieved Jul 13, 2026, from https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title42-section426&num=0&edition=prelim Waiting until 68 or 70 to claim your check does not cost you your hospital insurance.
Frequently Asked Questions
Do I need to sign up for Medicare at 65?
It depends on when your benefits started. If your Social Security (or Railroad Retirement Board) benefits began at least four months before you turn 65, no: you're enrolled automatically and there's nothing to file. If you're not drawing those benefits yet, or you started them closer to your birthday than that, then yes, you have to sign up yourself, and you'll want to do it during your Initial Enrollment Period.Centers for Medicare & Medicaid Services. (n.d.). Open Enrollment. medicare.gov. Retrieved Sep 2, 2026, from https://www.medicare.gov/health-drug-plans/open-enrollment
Does Medicare enroll you automatically in Part B too?
If you've been on Social Security long enough to be auto-enrolled, yes. Medicare's guidance says Part B is added automatically alongside Part A.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare The difference is that Part B has a monthly premium ($202.90 in 2026), so Medicare lets you turn it down if you have other coverage, like an active employer plan, that you'd rather keep for now.Centers for Medicare & Medicaid Services. (2026). 2026 Medicare Parts A & B Premiums and Deductibles. cms.gov. Retrieved Aug 7, 2026, from https://www.cms.gov/newsroom/fact-sheets/2026-medicare-parts-b-premiums-deductibles
When will my Medicare card arrive?
For people who are auto-enrolled, Medicare says the card comes in the mail about three months before their coverage starts.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare If you have to sign up yourself, your card follows after you complete enrollment through Social Security.
What if I'm not taking Social Security yet?
Then nobody enrolls you automatically. You sign up through Social Security, online at ssa.gov or by phone, during your Initial Enrollment Period.Centers for Medicare & Medicaid Services. (n.d.). How do I sign up for Medicare?. medicare.gov. Retrieved Jul 15, 2026, from https://www.medicare.gov/basics/get-started-with-medicare/sign-up/how-do-i-sign-up-for-medicare Waiting too long without qualifying job-based coverage can leave you with a Part B late-enrollment penalty, so don't let the date slip. It does not cost you Part A: someone who reaches 65 without claiming Social Security files an application for hospital insurance, and someone who claims those benefits later than 65 need not file one at all.Office of the Law Revision Counsel, U.S. House of Representatives. (n.d.). 42 U.S.C. 426 — Entitlement to hospital insurance benefits (Office of the Law Revision Counsel, uscode.house.gov). uscode.house.gov. Retrieved Jul 13, 2026, from https://uscode.house.gov/view.xhtml?req=granuleid:USC-prelim-title42-section426&num=0&edition=prelim
Learn More
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