Delaying Medicare Past 65: When It's Safe (and When It's a Trap) (2025)

You do not have to enroll in Medicare at 65. If you or your spouse are still working and covered by an employer group health plan, you can delay Medicare without penalty — and in many cases, delaying Part B is the smart financial move. But if you delay for the wrong reasons or miss your Special Enrollment Period window, you'll pay a permanent premium penalty for the rest of your life.

The Penalty: 10% Per Year, Permanently

Medicare Part B has a late enrollment penalty that is unlike most insurance penalties — it never goes away. For every 12-month period that you were eligible for Medicare Part B but did not enroll, and did not have qualifying coverage, 10% is added permanently to your monthly Part B premium.

When Delaying Is Safe — and Smart

There is one situation in which delaying Medicare Part B is not only safe but financially sensible: you are actively employed and covered by an employer group health plan (GHP) from a current employer with 20 or more employees — either your own employer or your spouse's employer.

In this situation:

• The employer plan is primary; Medicare would be secondary — paying two premiums for redundant coverage makes no financial sense
• You accrue no late enrollment penalty as long as you have this qualifying coverage
• When employment or coverage ends, you receive a Special Enrollment Period (SEP) of 8 months to sign up for Part B without penalty

What Counts as Qualifying Coverage to Delay Part B

Part A vs. Part B: Different Rules, Different Decisions

Part A and Part B are treated differently, and the right decision for each is usually different.

Part A (Hospital Coverage)

For most people — those who worked at least 40 quarters (10 years) paying Medicare taxes — Part A is free. There is almost no reason not to enroll in Part A at 65, even if you're still working and have employer coverage. Part A has no premium to avoid, and it provides hospital coverage as a backup if your employer plan falls short.

The one exception: HSA contributors. If you have a Health Savings Account and are actively making contributions, enrolling in any part of Medicare (including Part A) ends your HSA contribution eligibility. See the HSA section below for details.

Part B (Medical Coverage)

Part B has a $185.00/month premium in 2025. If you have employer coverage as the primary plan, you are paying two premiums — the employer plan premium and Part B — for overlapping coverage. This is the situation where delaying Part B makes financial sense. Skip Part B only if you have active qualifying employer coverage. The moment that employment ends, start your Part B enrollment immediately — your 8-month SEP window opens automatically.

The HSA Trap: Stop Contributing Before You Enroll

This catches many working seniors by surprise. Once you enroll in any part of Medicare — including Part A — you are no longer eligible to contribute to a Health Savings Account (HSA). Additionally, Social Security retroactively applies Medicare Part A coverage up to 6 months back when you claim Social Security benefits after age 65. This means:

• If you enroll in Part A at 65, your HSA contributions must stop immediately
• If you claim Social Security after 65, you will automatically be enrolled in Part A, potentially creating a retroactive period during which your HSA contributions were impermissible — resulting in IRS excise tax penalties

The safe approach: If you want to continue HSA contributions past 65, delay both Part A and Social Security. Stop HSA contributions at least 6 months before you plan to enroll in Medicare (or claim Social Security) to avoid the retroactive overlap.

This is a nuanced situation with real tax consequences. Consult a tax advisor or SHIP counselor before making decisions if you have an active HSA at 65.

The Special Enrollment Period (SEP): Your 8-Month Window

When you have been delaying Medicare Part B due to active employer coverage and that coverage ends, you do not have to wait for a general enrollment period. You receive a Special Enrollment Period that gives you 8 months to sign up for Part B without penalty, starting from whichever comes first:

• The month your employment ends, or
• The month your employer group health coverage ends

Note: these two events can happen at different times. If you retire but your employer coverage continues for a few months as a retiree benefit, your SEP clock starts when the coverage actually ends — not when you stopped working.

The Small Employer Problem: Fewer Than 20 Employees

The safe-to-delay rules assume your employer has 20 or more employees. If your employer has fewer than 20 employees, the rules flip:

• 20+ employees: Employer plan is primary; Medicare is secondary. Delaying Part B is safe and financially sensible.
• Fewer than 20 employees: Medicare is primary; the employer plan is secondary. If you don't have Part B and receive medical services, Medicare — which you don't have — would normally pay first. Your employer plan, as the secondary insurer, may deny or sharply reduce claims for services that Medicare would have covered. The result: large unexpected out-of-pocket costs.

If you are 65+ and working for a small employer (under 20 employees), you should generally enroll in Part B to avoid this primary/secondary coverage gap.

Part D: Delaying Prescription Drug Coverage

Part D has its own late enrollment penalty, separate from the Part B penalty. The Part D penalty is 1% of the national base beneficiary premium per month you were eligible but not enrolled without creditable drug coverage. Unlike the Part B penalty (which is calculated in full-year increments), the Part D penalty accumulates monthly and is also permanent.

You can delay Part D without penalty if you have creditable prescription drug coverage — coverage at least as good as standard Part D. Creditable coverage includes:

• Employer group health plan drug coverage (must be designated "creditable" — your employer must notify you annually)
• VA prescription drug benefits
• TRICARE pharmacy coverage
• FEHB (Federal Employees Health Benefits) drug coverage

When you lose creditable drug coverage, you have 63 days to enroll in a Part D plan without penalty. Missing this 63-day window starts the penalty clock.

The Retirement Transition Checklist

Use this checklist when approaching retirement or a change in employment status to determine your Medicare enrollment obligations:

Self-Employed People and Sole Proprietors

If you are self-employed, you do not have an "employer group health plan" in the sense Medicare requires. Individual health insurance — even a comprehensive plan you purchase through your business — does not count as qualifying coverage for delaying Part B without penalty. When you turn 65, you should enroll in Medicare during your Initial Enrollment Period. Continuing to pay for an individual health plan after enrolling in Medicare rarely makes financial sense; Medicare typically provides better value.

Frequently Asked Questions