Turning 65? Here’s What You Need to Know About Medicare

1. Do I Need to Sign Up for Medicare or Will It Happen Automatically?

That depends on your situation:

If you’re already receiving Social Security or Railroad Retirement Board (RRB) benefits, you’ll be automatically enrolled in Medicare Parts A and B. Your coverage will begin the first day of the month you turn 65—or the month before if your birthday falls on the 1st.
If you’re not receiving Social Security yet, you’ll need to actively enroll in Medicare. You can do so by visiting SSA.gov/medicare, calling Social Security, or applying in person.

Tip: You can apply up to three months before your 65th birthday month to ensure coverage begins on time.

2. Should I Sign Up for Part A and Part B?

Part A (Hospital Insurance) is usually premium-free if you or your spouse worked and paid Medicare taxes for at least 10 years. Most people enroll in Part A when they turn 65, even if they are still working.
Part B (Medical Insurance) has a standard monthly premium, which is set annually. For 2025, it is $185, though it may be higher depending on your income. If you’re still working and you have health insurance through your employer, you can often delay Part B enrollment without penalty.

3. What’s My Medicare Enrollment Timeline?

Here are the key timeframes:

Initial Enrollment Period (IEP): This 7-month window starts 3 months before your 65th birthday month and ends 3 months after. Enrolling early ensures your coverage starts on time.
Special Enrollment Period (SEP): Available if you’re working and covered by group health insurance. You can enroll anytime while covered, or within 8 months of the coverage ending, without penalty.
General Enrollment Period (GEP): Runs January 1 – March 31 each year, but this can result in delayed coverage and late penalties if you missed your IEP or SEP.

5. Still Working at 65? Here’s How Medicare Works With Employer Coverage

Many people are still working at 65 and beyond, and have health insurance through their employer—or through a spouse’s employer. If that’s you, here’s what you need to know:

If Your Employer Has 20 or More Employees

You can often delay Medicare Part B (which has a monthly premium) without a penalty. Rules can vary depending on your specific employer coverage. Your employer plan pays first, and Medicare acts as a secondary payer. This allows you to postpone enrolling in Part B until your employer coverage ends. Always confirm with your HR department or Social Security before delaying Part B.

If Your Employer Has Fewer Than 20 Employees

In this case, Medicare pays first, and your employer plan is secondary. You’ll likely want to enroll in both Part A and Part B when you turn 65 to avoid any gaps in coverage.

COBRA, Retiree Plans, and Marketplace Coverage Don’t Count

If you're covered by COBRA, a retiree health plan, or an Affordable Care Act (ACA) Marketplace plan, be aware that these are not considered active employer coverage. They do not qualify you for a Special Enrollment Period (SEP), and delaying Part B could result in permanent late penalties.

How to Transition From Employer Coverage to Medicare

When you or your spouse stops working and your group health coverage ends, you’ll have an 8-month Special Enrollment Period to sign up for Part B without a penalty. To avoid any break in coverage, it’s smart to start the transition about 1–2 months before your employer coverage ends.

Here’s what to do:

Enroll in Part B through Social Security at SSA.gov/medicare.
Submit two important forms:
CMS-40B (Application for Part B)
CMS-L564 (Request for Employment Information)—your employer must fill this out to verify coverage.
Coordinate your effective dates to ensure continuous coverage as you switch from employer insurance to Medicare.

Tip: If you have a Health Savings Account (HSA), stop contributing to it at least 6 months before you apply for Medicare to avoid IRS tax penalties.