How to Sign Up for Medicare: Step-by-Step Guide
Signing up for Medicare is usually straightforward.
The steps depend on two things: whether you already receive Social Security benefits, and whether you have health insurance through a current job.
This guide walks through enrolling in Medicare Part A and Part B, the deadlines that can lead to late penalties, and what to do once your coverage is in place.
Quick answer
- Already getting Social Security? You'll likely be enrolled in Parts A and B automatically and receive your card in the mail.
- Not getting Social Security yet? Apply at SSA.gov, by phone at 1-800-772-1213, or at a local Social Security office.
- Best timing: Apply in the three months before the month you turn 65 so coverage starts on time.
Step 1: Find Out Whether You'll Be Enrolled Automatically
Your first job is figuring out which path applies to you.
You'll usually be enrolled automatically if…
- You're already receiving Social Security or Railroad Retirement Board benefits at least four months before you turn 65.
- You're under 65 and have received Social Security or certain Railroad Retirement disability benefits for 24 months.
- You have ALS and receive Social Security disability benefits (Medicare starts the month disability benefits begin).
You'll usually need to apply if…
- You're turning 65 and haven't started Social Security yet.
- You delayed Part B because of job-based coverage.
- You have End-Stage Renal Disease (ESRD).
- You live in Puerto Rico or another country. You'll get Part A automatically, but you have to sign up for Part B.
If you're enrolled automatically, your Medicare card usually arrives about three months before coverage begins.
Disability, ESRD, and railroad situations follow their own rules. Social Security's Medicare sign-up page can confirm which process applies to you.
Automatic enrollment includes Part B, which has a monthly premium.
If you have qualifying coverage through a current job, you can follow the instructions with your card to decline Part B for now.
Step 2: Know When to Apply
Most people first enroll during a seven-month Initial Enrollment Period.
It includes the three months before the month you turn 65, your birthday month, and the three months afterward.
When you sign up within that window affects when coverage starts.
| When you sign up | When coverage starts |
|---|---|
| Three months before your birthday month | First day of your birthday month |
| During your birthday month | First day of the following month |
| Three months after your birthday month | First day of the month after you sign up |
| General Enrollment Period (Jan. 1–Mar. 31) | First day of the month after you sign up |
Enrolling in the three months before your birthday month generally allows coverage to start the month you turn 65.
If you sign up during the General Enrollment Period because you missed your earlier window, you may also owe a late enrollment penalty.
Birthday on the 1st? Medicare treats you as turning 65 the month before, so your window shifts back one month.
Medicare explains these timing rules on its When Does Medicare Coverage Start? page.
Step 3: Apply Through Social Security
The Social Security Administration handles enrollment in Medicare Parts A and B, even though Medicare itself is run by a different agency.
By phone
Call Social Security at 1-800-772-1213 (TTY 1-800-325-0778).
In person
Find your nearest office with the SSA office locator. Appointments are recommended.
If you or your spouse worked for a railroad, apply through the Railroad Retirement Board instead.
You don't have to start collecting Social Security retirement payments just to enroll in Medicare.
What to have ready before you apply
- Your Social Security number
- Proof of birth date and U.S. citizenship or lawful residence, if Social Security asks for it
- Details of current employer or union health coverage, including start dates
- Your spouse's information if you're applying based on their work record
Step 4: Review Your Medicare Card and Coverage Dates
After your application is processed, you'll receive your red, white, and blue Medicare card.
The card shows the start date for your Part A and Part B coverage. They aren't always the same date.
Check these dates carefully if you're timing Medicare around the end of employer coverage. A one-month gap can mean an uncovered doctor visit or hospital stay.
If a date looks wrong, contact Social Security before assuming when your coverage starts.
Step 5: Decide How You Want to Receive Your Benefits
Once you have Parts A and B, you'll choose between two main ways to receive your Medicare benefits.
| Feature | Original Medicare | Medicare Advantage |
|---|---|---|
| See any provider who accepts Medicare nationwide | Yes | Usually network-based |
| Prescription drug coverage included | No, add Part D | Usually |
| Can add a Medigap policy | Yes | No |
| Annual out-of-pocket limit for Part A and Part B services | No | Yes |
Original Medicare has no annual out-of-pocket limit for Part A and Part B services. Medigap can help cover many of those expenses.
For a deeper look at the tradeoffs, see our comparison of Medigap Plan G vs. Medicare Advantage in Florida.
That's especially true for Floridians who spend part of the year in another state, since most Medicare Advantage networks are local.
Learn more in our Medicare Supplement resources and overview of Medicare Advantage plans.
What If You're Still Working at 65?
You may be able to delay Part B without a penalty if you have group health coverage through your own or your spouse's current employment.
Employer size is usually the key detail:
20 or more employees
Your employer plan generally pays first, so delaying Part B is often reasonable.
Fewer than 20 employees
Medicare generally pays first. Many small-employer plans expect you to enroll in Part B at 65 and could deny claims if you don't.
There are exceptions, including some multi-employer plans and coverage tied to disability.
Confirm with your benefits administrator how your plan coordinates with Medicare before deciding to delay.
Many people still enroll in premium-free Part A at 65, since it usually costs nothing. The exception is anyone still contributing to a Health Savings Account.
HSA contributors: timing matters
HSA eligibility is determined month by month. You can no longer make or receive HSA contributions for any month you're enrolled in Medicare.
Enrolling at 65: If you sign up during your Initial Enrollment Period, Part A generally starts no earlier than your 65th birthday month. Stop contributions before that month.
Applying after 65: Premium-free Part A is generally backdated up to six months from the date you apply, but no earlier than your 65th birthday month. Stopping contributions six months before you apply helps avoid a tax penalty.
Applying for Social Security retirement benefits after 65 triggers Part A too, so the same lookback applies.
The Medicare & You handbook covers these rules, and a tax advisor can confirm your exact cutoff.
How to Sign Up After Losing Employer Coverage
If you delayed Part B because you had qualifying coverage from your own or your spouse's current employment, you get a Special Enrollment Period.
You can sign up anytime while you're still covered through that job.
You can also sign up during the eight months that begin the month after your employment or coverage ends, whichever comes first.
To apply, you'll generally submit two forms to Social Security:
- CMS-40B: Application for Enrollment in Medicare Part B.
- CMS-L564: Request for Employment Information, completed by your employer to prove your coverage.
If your employer won't complete the CMS-L564, Social Security accepts other proof, such as pay stubs showing health premiums or an insurance card.
COBRA and retiree coverage don't count
Neither COBRA nor retiree health coverage is based on current employment.
If you rely on either one and skip Part B, you may face a late penalty and a gap in coverage.
Your eight-month window starts when the job ends, not when COBRA ends.
Keep in mind that this eight-month window applies only to Part B.
Special Enrollment Periods for Medicare Advantage and Part D are generally much shorter, often about two months after the month your coverage ends.
The exact window depends on the type of coverage you lost, so don't wait for the Part B deadline to arrange drug coverage.
What Happens If You Sign Up Late?
Missing your enrollment window can lead to late penalties.
The Part B and Part D penalties generally continue for as long as you have that coverage. The Part A penalty is temporary.
Part B late penalty: generally ongoing
Your premium generally goes up 10% for each full 12-month period you could have had Part B but didn't.
You usually pay it for as long as you have Part B.
Part D late penalty: generally ongoing
If you go 63 or more days in a row without Part D or other creditable drug coverage after your enrollment period ends, a penalty is generally added to your premium.
You pay it for as long as you have Medicare drug coverage.
Part A late penalty: temporary
Applies only if you have to buy Part A, usually because you or your spouse have fewer than 40 work quarters.
Your premium may increase by 10%, and you pay it for twice as many years as you could have had Part A but didn't.
Most people get Part A premium-free and never face this penalty.
Medicare explains each penalty on its avoiding late penalties page.
Common Sign-Up Mistakes to Avoid
Waiting until your birthday month to apply
Coverage then starts the following month, which can leave a short gap.
Assuming any employer coverage lets you delay Part B
Small-employer plans, COBRA, and retiree plans usually don't protect you from penalties.
Thinking you need to start Social Security first
You can enroll in Medicare and still delay retirement benefits.
Forgetting about your HSA
Retroactive Part A can turn recent contributions into excess contributions.
Missing your Medigap Open Enrollment Period
After it ends, insurers can generally use your health history to decide whether to sell you a policy.
What to Do After You Enroll
Once your Part A and Part B coverage is confirmed:
- Double-check your Part A and Part B start dates.
- Decide whether to stay with Original Medicare or enroll in Medicare Advantage.
- Arrange prescription drug coverage so you avoid the Part D penalty.
- Consider whether a Medicare Supplement policy makes sense for you.
- Confirm your doctors accept the coverage you choose.
Your Medigap Open Enrollment Period only happens once.
It starts the first month you're both 65 or older and enrolled in Part B. Our Florida Medigap Open Enrollment guide covers the details.
During those six months, insurers generally cannot deny you a Medigap policy or charge more because of your health.
If you have Medicare before 65 because of a disability or ESRD, your Medigap options may be different. You'll generally get your federal six-month Medigap Open Enrollment Period when you turn 65.
Outside that window, federal guaranteed issue rights may apply in certain situations, depending on the coverage you had and your circumstances.
Medicare lists them on its When Can I Buy a Medigap Policy? page.
If you plan to keep Original Medicare, your open enrollment period is usually the best time to buy a Medicare Supplement policy.
Explore our 2026 guide to Medicare Supplement plans in Florida to compare your options.
Already enrolled and want to change plans? Medicare's Annual Enrollment Period runs Oct. 15 through Dec. 7 each year for Medicare Advantage and Part D changes. It doesn't apply to first-time sign-ups for Part A and Part B.
Where to Get Help Signing Up for Medicare
You don't have to figure this out alone.
- SHINE (Serving Health Insurance Needs of Elders): Florida's free, unbiased Medicare counseling program, run by the Florida Department of Elder Affairs. Call 1-800-963-5337 or visit floridashine.org to find a counselor near you.
- Social Security: For questions about your application, enrollment status, or coverage dates, call 1-800-772-1213.
- Medicare: For questions about coverage and plans, call 1-800-MEDICARE (1-800-633-4227).
The Bottom Line
Start by finding out whether you'll be enrolled automatically.
If you need to apply, do it through Social Security, ideally in the three months before your 65th birthday month.
If you're still working, confirm your employer coverage qualifies before delaying Part B, since the Part B late penalty generally lasts as long as you have Part B.
Once Parts A and B are in place, decide how you'll receive your benefits. If you choose Original Medicare, your one-time Medigap Open Enrollment Period is usually the best time to add a supplement.
With over 20 years of experience, Mark Prip is a dedicated licensed Medicare insurance agent in Florida. His expertise lies in simplifying the Medicare coverage process by providing comprehensive education to beneficiaries.
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