Do Federal Retirees Have to Sign Up for Medicare Part B?

Federal retirees do not automatically have to enroll in Medicare Part B, but most will eventually need it

If you retired from the federal government and have federal employee health insurance (FEHB), you can delay enrolling in Medicare Part B without penalty — as long as you keep your FEHB coverage active. This is different from the general public, where waiting to sign up for Part B after 65 usually costs you more in premiums for life. Federal retirees get what's called creditable coverage, which means your FEHB plan counts as health insurance that is at least as good as Medicare Part B.

However, "you don't have to" is not the same as "you shouldn't." Many federal retirees eventually drop FEHB and move to Medicare Part B, either because FEHB premiums rise too high, because they move out of the FEHB service area, or because they reach an age where Medicare becomes the simpler choice. Understanding when you might want to switch, and what happens if you do, matters more than the rule itself.

Key Takeaways

Federal employees and retirees with FEHB coverage can delay Medicare Part B enrollment without penalty as long as FEHB stays active.
FEHB is considered creditable coverage, meaning it meets the standard of Part B and protects you from late-enrollment penalties if you join Medicare later.
When you do enroll in Part B — whether now or years from now — you will pay a monthly premium that increases if you delay past 65.
If you drop FEHB to use Medicare alone, you must enroll in Part B during your initial enrollment window or face permanent premium increases.
The Office of Personnel Management (OPM) publishes annual guidance on how FEHB and Medicare work together for federal retirees.

How FEHB protects you from Part B penalties

The federal government recognizes FEHB as creditable coverage because it covers the same services that Medicare Part B does — doctor visits, outpatient care, lab work, and preventive services. This means you are not penalized for waiting to enroll in Part B after you turn 65, as long as you stay enrolled in FEHB the whole time.

The penalty itself is real for people who miss the important date: for every 12 months you delay Part B enrollment after you turn 65, your monthly premium increases by 10 percent, and that increase is permanent. A federal retiree with FEHB avoids this entirely. You can enroll in Part B at 67, 70, or even later, and your premium will be the standard rate for your age — not inflated by the penalty.

This protection only holds if you maintain continuous FEHB coverage. If you drop FEHB and go without creditable coverage for any month, you lose the protection. You then have eight months from the date you lose coverage to enroll in Part B without penalty; after that, the 10 percent-per-year increase applies.

When federal retirees typically switch to Medicare Part B

Many federal retirees stay on FEHB for years after turning 65, and some keep it for life. Others move to Medicare Part B because FEHB premiums become expensive, because they relocate outside a plan's service area, or because they reach an age where managing two insurance systems feels burdensome. There is no single right time — it depends on your health, your location, and your finances.

If you do decide to drop FEHB and enroll in Part B, the timing matters. You should enroll in Part B before you cancel FEHB, or during the same month. If you let FEHB lapse first, you have a 63-day window to enroll in Part B without losing creditable-coverage protection. After that window closes, late-enrollment penalties kick in.

Some retirees coordinate the switch with a move, a change in health status, or a life event. Others straightforward compare the cost of FEHB premiums against the cost of Part B premiums plus a Medigap or Medicare Advantage plan, and choose whichever is cheaper. OPM publishes worksheets and comparison tools to help with this decision.

What happens to your FEHB coverage if you enroll in Part B

Enrolling in Medicare Part B does not automatically cancel your FEHB coverage. You can have both at the same time. In fact, many federal retirees keep FEHB as a supplement to Medicare, because FEHB often covers things Medicare does not — like dental, vision, and hearing aids — and because FEHB has no deductibles or copays in many plans.

If you want to drop FEHB after enrolling in Part B, you can do so at any time during the Federal Employees Health Benefits Program (FEHBP) open season, which runs from the second Monday in November through the second Monday in December each year. You can also drop FEHB if you experience a may have access to life event, such as moving out of the service area or losing may be able to access.

Once you drop FEHB, you cannot re-enroll unless you become a federal employee again or experience certain may have access to events. This is a one-way door for most retirees, so the decision to leave FEHB should be deliberate.

How Part B premiums work for federal retirees

Medicare Part B premiums are based on your income from two years prior. For 2024, the standard monthly premium is $164.90 for most people, but if your modified adjusted gross income (MAGI) exceeds certain thresholds, you pay more through a surcharge called an Income-Related Monthly Adjustment Amount (IRMAA). These thresholds and amounts change each year.

Federal retirees pay the same Part B premiums as anyone else. There is no special federal retiree rate. However, because you can delay enrollment without penalty, you have more flexibility in timing your enrollment to manage your tax situation or income if that matters to your IRMAA calculation.

Part B premiums are usually deducted from your Social Security check. If you are not yet receiving Social Security, you will receive a bill from Medicare. If you have both FEHB and Part B, you will pay both premiums — FEHB to your health plan and Part B to Medicare.

Coordinating FEHB and Part B coverage

If you keep both FEHB and Part B active, Medicare becomes your primary payer for services covered by both plans, and FEHB becomes secondary. This means Medicare pays first, and FEHB covers what Medicare does not — copays, coinsurance, and services outside Medicare's scope.

This coordination can work well if your FEHB plan is designed to work alongside Medicare. Some FEHB plans are explicitly "Medicare-coordinated" and assume you will have Part B. Others are not, and may have higher out-of-pocket costs if you use them as secondary coverage. Before you enroll in Part B while keeping FEHB, check your plan's summary of benefits to see how it coordinates with Medicare.

You will also need to make sure both plans have your correct information and that claims are submitted to the right payer in the right order. This usually happens automatically, but errors can occur. If you receive a bill you think is wrong, contact both your FEHB plan and Medicare to verify who should have paid.

What to do if you are unsure about your coverage

The Office of Personnel Management (OPM) maintains a website with resources for federal employees and retirees, including detailed guides on how FEHB and Medicare interact. You can also contact your FEHB plan directly — they have staff trained to answer questions about Medicare coordination.

If you are approaching 65 or thinking about dropping FEHB, consider scheduling a conversation with your plan's customer service line. They can walk you through the costs of staying on FEHB versus switching to Medicare Part B, and they can explain how your specific plan coordinates with Medicare if you choose both.

You can also contact Medicare directly at 1-800-MEDICARE to ask about Part B enrollment, premiums, and how your FEHB coverage affects your options. Medicare representatives can confirm whether your FEHB plan is creditable coverage and answer questions about enrollment important date.

Frequently Asked Questions

Can I enroll in Medicare Part B while I still have FEHB?

Yes. You can have both FEHB and Medicare Part B at the same time. Medicare becomes primary for services both plans cover, and FEHB covers the gaps. You do not have to choose one or the other.

What happens to my FEHB if I turn 65 and do nothing?

Your FEHB coverage continues unchanged. You do not lose it at 65, and you do not automatically enroll in Medicare. You keep FEHB until you actively cancel it or until you no longer meet the may be able to access requirements.

If I drop FEHB, can I get it back later?

Once you drop FEHB as a retiree, you generally cannot re-enroll unless you become a federal employee again or experience a may have access to life event like moving out of the service area. Dropping FEHB is usually permanent, so make sure you are ready before you cancel.

Will I owe a penalty if I wait until age 70 to enroll in Part B?

No, as long as you keep FEHB active the entire time. Your creditable-coverage status protects you from late-enrollment penalties. You can enroll in Part B at any age without penalty, and your premium will be the standard rate.

How do I know if my FEHB plan is creditable coverage?

Your FEHB plan summary or your plan's customer service line will confirm this. Most FEHB plans are creditable coverage by default, but it is worth verifying with your specific plan if you are unsure.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.