Turning 65 is the usual time to start Medicare, and the rules around it are stricter than most people expect. Enroll on time and you avoid penalties. Miss your window and some of those penalties last for life. This guide walks you through the timeline, the steps, and the special rules if you're still working.
It's written for people turning 65 who are new to Medicare. If you're already enrolled and want to change plans, see our guides to Medicare Advantage, Medigap and Part D.
Your Medicare Timeline
Your first chance to sign up is called your Initial Enrollment Period. It lasts seven months and is built around your 65th birthday.
About 6 months before you turn 65: get your bearings
Learn what the four parts of Medicare cover, which our Medicare 101 guide explains in plain English. Make a list of your doctors and your prescriptions. Find out whether you will get Social Security benefits, and whether you or your spouse still have job-based coverage.
3 months before your birthday month: your window opens
Your seven-month window starts three months before the month you turn 65. It includes your birthday month and ends three months after it. If you sign up in the first three months, your coverage can start the first day of your birthday month.
Your birthday month and the 3 months after
You can still enroll, but coverage starts later. If you sign up in your birthday month or after, your coverage generally starts the month after you enroll, which can leave a gap if you've lost other coverage.
After the window closes
If you miss your window and don't have qualifying job-based coverage, you may have to wait for the General Enrollment Period (January 1 to March 31). Your coverage then starts the month after you sign up. For Part B, you may also pay a late-enrollment penalty: 10% more for each full 12 months you could have had Part B but didn't, for as long as you have it.
Step-by-Step: What to Do
Step 1: Find out if you'll be enrolled automatically
If you already receive Social Security or Railroad Retirement benefits at least four months before you turn 65, you're usually signed up for Medicare Parts A and B automatically, and your Medicare card arrives in the mail about three months before your birthday. If you don't receive those benefits yet, you need to sign up yourself.
Step 2: Check whether you have other coverage
Do you or your spouse still work and have a group health plan through that job? This affects whether you should take Part B now. We cover this in If You're Still Working at 65 below. Coverage through COBRA or retiree plans is treated differently from active job-based coverage, so check before you delay anything.
Step 3: Sign up for Part A and Part B
If you aren't enrolled automatically, you can sign up for Parts A and B online with the Social Security Administration at SSA.gov/medicare/sign-up (opens in a new tab), or call 1-800-772-1213. Part A is premium-free for most people who worked and paid Medicare taxes for about 10 years. Part B has a monthly premium. The standard Part B premium was $202.90 a month in 2026, and the 2027 amount is usually announced in November.
Step 4: Choose how you want to get your coverage
Most people choose between two paths. Neither is right for everyone.
- Original Medicare plus a Medigap plan and a Part D drug plan. You can see any doctor who accepts Medicare. Read our Medigap guide.
- Medicare Advantage. One private plan that includes your hospital and medical coverage, and often drugs and extras like dental, vision and hearing. Read our Medicare Advantage guide.
Step 5: Add drug coverage
If you choose Original Medicare, you'll want a standalone Part D plan. If you go without drug coverage that is at least as good as Medicare's for 63 days or more, a late-enrollment penalty can be added to your Part D premium for as long as you have it. Our Part D guide walks through comparing plans step by step.
Step 6: Check your doctors and your prescriptions
Before you choose a plan, check that your doctors and hospital are covered, and that your medications are on the plan's drug list. Medicare Advantage plans use networks. Original Medicare with Medigap does not.
Step 7: Enroll, and keep your confirmation
Enroll in your plan through the plan, Medicare.gov, 1-800-MEDICARE or an agent. Keep your confirmation and your new member ID card, and make sure your start date matches the date your other coverage ends.
Would you like help with your first Medicare choices?
There is no charge for our help. Tell me when your birthday is, whether you're still working, and which doctors and drugs matter to you, and I'll walk you through your options. A plan costs the same whichever way you enroll.
If You're Still Working at 65
You don't always have to take Part B at 65. It depends on your coverage.
- Your employer has 20 or more employees. The job-based plan usually pays first, and you can generally delay Part B without a penalty while you or your spouse are actively working and covered by that plan.
- Your employer has fewer than 20 employees. Medicare often pays first, so you generally should enroll in Part B on time.
- You have COBRA or retiree coverage. These generally don't count as active job-based coverage, so waiting can bring the Part B penalty.
- When the job or coverage ends. You usually get an eight-month Special Enrollment Period to sign up for Part B without a penalty. Ask your employer for proof of coverage dates.
Rules differ by company size and plan type, so ask your HR department before you decide. We can also help you work through it.
Common Mistakes to Avoid
- Assuming COBRA or retiree coverage lets you wait. It usually doesn't. Check before you delay Part B.
- Waiting until your birthday month or later to enroll. Your coverage start gets pushed back, which can leave a gap.
- Forgetting the Medigap window. Your six-month Medigap open enrollment period starts when your Part B does. After that, health questions may apply.
- Skipping drug coverage. A late-enrollment penalty can follow you for as long as you have Part D.
- Not checking your doctors. Make sure your doctors and hospital work with the plan you pick.
FAQs
Do I have to sign up for Medicare at 65?
Not always. If you have qualifying coverage through active work, you may be able to wait without a penalty. If you don't, you generally should sign up during your Initial Enrollment Period. If you take Social Security, Part A starts automatically.
Will I get my Medicare card automatically?
If you already receive Social Security or Railroad Retirement benefits, usually yes, about three months before you turn 65. Otherwise you sign up yourself.
How much does Medicare cost?
Part A is premium-free for most people. Part B has a monthly premium that is higher for people with higher incomes. Drug plans and Medicare Advantage plans have their own premiums, and some have $0 plan premiums. You may also pay deductibles, copays and coinsurance.
Can I keep my employer plan and have Medicare?
Yes. Many people do. How the two work together depends on your employer's size and on which one pays first. Ask your benefits administrator.
When should I start looking at plans?
About six months before you turn 65. That gives you time to learn your options before your window opens.
Official Sources
- Social Security: Sign up for Medicare (opens in a new tab) or call 1-800-772-1213
- Medicare.gov (opens in a new tab) or call 1-800-MEDICARE
- Medicare Plan Finder (opens in a new tab)
- CMS.gov (opens in a new tab)
Related Guides
- Medicare 101: a plain-English guide
- Free download: Medicare, made simple (PDF guide)
- Medicare Advantage in Tampa Bay, explained
- Medicare Supplement (Medigap) in Tampa Bay, explained
- How to enroll in or switch Part D plans