Retirement & Tax Planning Answers
Should Federal Retirees Enroll in Medicare Part B If They Have FEHB?
Quick answer
There is no universal answer, but there is a trap most federal retirees miss. FEHB is creditable coverage for Medicare Part D, so you can skip Part D without a penalty. FEHB held as a retiree is not the kind of coverage that lets you delay Part B penalty-free, because only coverage from active employment does that. A federal retiree who declines Part B at 65 and later changes their mind faces a permanent late enrollment penalty of 10% of the premium for every 12 months they could have enrolled but did not, plus a wait for the next General Enrollment Period. Federal employees still working past 65 are in a different position entirely and can safely delay Part B while covered through active employment, with a special enrollment period after they separate. Beyond the penalty question, the decision is plan-specific: the 2026 standard Part B premium is $202.90 per month, and a number of FEHB plans waive deductibles and cost sharing, or reimburse part of the Part B premium, once Medicare becomes the primary payer.
The distinction that governs everything here is retiree coverage versus active-employment coverage. A private-sector worker covered by a large employer group plan can delay Part B without penalty because they are still working. A federal retiree carrying FEHB is not working, and Medicare does not treat FEHB differently from any other retiree plan for this purpose.
If you are still a federal employee at 65, you are in the protected group. You can decline Part B, keep FEHB through active employment, and enroll during a special enrollment period that runs for eight months after that employment ends, with no penalty.
Once you are retired, the math becomes plan-specific rather than general. Several FEHB carriers waive your deductible, copays, and coinsurance when Medicare pays first, and some offer a Part B premium reimbursement arrangement. In those plans, adding Part B can approach cost-neutral. In others it is a straightforward second premium for coverage that overlaps.
Income matters too. IRMAA raises the Part B and Part D premium for higher-income retirees based on income from two years prior, so a large Roth conversion at 63 can raise the cost of the Part B decision you make at 65. These two decisions are usually made by different people at different times, which is precisely how they end up in conflict.
The government continues paying roughly 70% to 75% of the FEHB premium in retirement. What changes is that the premium comes out of your annuity with after-tax dollars rather than pre-tax through payroll, which quietly raises the real cost in a way most retirement projections never show.
If you are approaching 65 and already retired, the Part B decision has a deadline attached to it and a permanent price for getting it wrong.
If you are still working at 65, you have room to wait, and waiting is often the better answer.
The right answer depends on which FEHB plan you carry. Two retirees with identical income can correctly reach opposite conclusions.
- Assuming FEHB lets a retiree delay Part B the way active employer coverage does. It does not.
- Confusing Part D creditability with Part B. FEHB is creditable for Part D only.
- Declining Part B without reading how your specific FEHB plan coordinates with Medicare.
- Making a large Roth conversion at 63 without checking what it does to the Part B premium at 65.
- Overlooking that FEHB premiums shift from pre-tax to after-tax at retirement.