The federal Medigap Open Enrollment Period is a one-time six-month period that starts the first month a person is age 65 or older and enrolled in Medicare Part B. It can begin even while employer coverage continues. Starting Part B early can therefore start the Medigap clock before the person plans to use a supplement.
A July 2026 Medicare discussion asked whether someone who carried Part B as secondary for years would receive a new Medigap enrollment period after retirement. Medicare ties the federal window to Part B, not the retirement date.
Start here: a practical action plan
- Open the official source and confirm the rule for your coverage, tax year, filing status, and deadline.
- Collect the notices, statements, plan documents, forms, and dated confirmations that control the decision.
- Replace the hypothetical figures with your actual amounts and keep the checked calculation with your records.
- Record the next deadline and obtain written confirmation after an enrollment, correction, appeal, or payment posts.
- Treating a forum answer, portal label, or plan summary as the final authority for a coverage or tax result.
- Comparing amounts on different tax, timing, or coverage bases without converting them to the same basis first.
- Discarding dated evidence that may be needed for an enrollment, appeal, tax correction, or claim dispute.
Put the Part B effective date on the calendar
Find the Medicare card or benefit letter showing the Part B effective date. For someone age 65 or older, the federal six-month Medigap open-enrollment period begins the first day of that month. It does not restart each year and generally does not wait for employer coverage to end.
During this window, insurers generally cannot refuse to sell available Medigap policies or price the applicant based on health problems. After the window, federal protections can be narrower, although guaranteed-issue events and stronger state rules may apply.
Coordinate Part B timing with active employer coverage
Someone with qualifying current-employment coverage may be able to delay Part B and later use a Special Enrollment Period. Delaying Part B can also delay the start of the federal Medigap window. The correct choice depends on payer order, employer plan costs, HSA contributions, medical needs, and state rules.
If Part B was activated while employer coverage remained primary, do not assume retirement creates another open-enrollment period. Ask the State Health Insurance Assistance Program and state insurance department about guaranteed-issue rights before dropping the employer plan.
Worked example: a six-month window used before retirement
Example: Dana, age 67, starts Part B on January 1 while still covered by a large current employer. Dana plans to retire October 31. The federal Medigap open-enrollment months are January through June, not November through April.
If Dana waits until retirement to shop, the federal window has ended under this example. A state rule or guaranteed-issue event may still protect the purchase, but that must be verified. Paying $202.90 monthly for ten months of 2026 Part B would also total $2,029 before IRMAA, even if the employer plan remains primary.
| Event | Example date | Effect |
|---|---|---|
| Part B begins | Jan. 1 | Medigap clock begins |
| Federal open enrollment | Jan. through Jun. | Six months |
| Retirement | Oct. 31 | Does not restart clock |
| Part B premiums, 10 months | $202.90 monthly | $2,029 before IRMAA |
Apply before old coverage ends when protection exists
Collect the employer termination notice, Medicare effective dates, and any proof supporting a guaranteed-issue right. Medicare advises retaining letters, notices, emails, and claim denials from prior coverage. Ask the Medigap insurer for the application deadline and required evidence.
Compare standardized plan benefits separately from insurer price, rating method, household discounts, and rate history. Do not cancel an existing plan until the Medigap policy is accepted and the effective date is confirmed. A new policy can include a 30-day free-look period when switching, during which both premiums may be due.
- Locate the Part B effective date.
- Mark the six federal enrollment months.
- Check state and guaranteed-issue protections.
- Confirm the Medigap effective date before cancellation.
Frequently asked questions
When does federal Medigap open enrollment begin?
It begins the first month a person is age 65 or older and enrolled in Medicare Part B.
Does retirement start a new six-month Medigap period?
No. Retirement alone does not restart the federal period if Part B began earlier.
Can the clock run while I still have employer coverage?
Yes. Medicare states that the period starts with Part B even when employer coverage continues.
Can I buy Medigap after the six months?
Possibly, but underwriting may apply unless a guaranteed-issue right or state protection is available.
Should I delay Part B to preserve Medigap enrollment?
That decision also affects Medicare deadlines, payer order, HSA eligibility, and medical coverage. Verify the whole situation before delaying.
Where can I get free state-specific help?
Contact the State Health Insurance Assistance Program and the state insurance department.
Sources and review notes
The calculations and scenarios in this guide are original BreadWinnr worked examples. We recalculated each example and checked that its parts match the stated total. Official sources support the financial concepts. Forum links document the reader problem that prompted the guide and are not treated as financial authority.
- Medicare.gov, when to buy Medigap
- Medicare.gov, Medigap open enrollment
- Reddit: employer coverage, Medicare, and Medigap timing
Read our research, testing, corrections, and source policy.
This guide provides general financial education. It does not account for your complete financial, tax, legal, or contractual situation.
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