Medigap’s Six-Month Window: The One Time No Insurer Can Ask About Your Health

Most Medicare deadlines come with a workaround. This one mostly does not. When you buy a Medicare supplement policy — a Medigap plan — you get one window in which federal law stops the insurer from looking at your health. It lasts six months and follows Part B, not your birthday. Once it closes, in most states, the insurer can ask about your health and price the answers, or decline you. The rule is simple; the timing is where households get caught.

What a Medigap Policy Is — and What It Is Not

Medigap is extra insurance from a private company that pays your share of Original Medicare’s costs — the deductibles, coinsurance, and copayments Parts A and B leave behind. Policies are standardized by letter (A through D, F, G, and K through N in most states), so a Plan G from one company covers the same things as a Plan G from another; only the premium differs. It is not Medicare Advantage, which replaces Original Medicare with a private plan and its network; you can have one or the other, never both. A policy covers one person, so a couple needs two. (Medicare.gov, Medigap basics; how Medigap works.)

The Window: Six Months, Anchored to Part B

Federal law gives you a one-time Medigap Open Enrollment Period. It runs six months and starts the first day of the month in which you are both 65 or older and enrolled in Part B. During those months an insurer may not refuse to sell you any Medigap policy it offers, may not use medical underwriting to decide whether to take you, and may not charge you more because of your health. (Medicare.gov, when to buy; 42 U.S.C. §1395ss(s)(2)(A).)

Two features matter more than the number. It does not repeat. And it is triggered by Part B, not by turning 65: sign up for Part B at 68 after leaving a job, and your six months begin then. (Medicare.gov, when to buy: the window “starts once you sign up for Part B and lasts for 6 months, even if you sign up for Part B while you still have employer coverage.”)

(CMS and NAIC, Choosing a Medigap Policy, March 2026, pp. 10–11 and 15–18; 42 U.S.C. §1395ss(s).)

After It Closes: Underwriting, and the Rights That Survive

Once the window closes, the protections end in most states: the insurer may ask about your health, charge more, or decline you. Federal law keeps a short list of guaranteed-issue rights — situations in which an insurer must sell you a policy, cover your pre-existing conditions, and not charge more for your health. Apply within 63 days of the old coverage ending. (CMS and NAIC guide, pp. 11, 15–18; 42 U.S.C. §1395ss(s)(3).)

• Your employer coverage ends. You have Original Medicare and a group plan that pays after Medicare — retiree, union, or COBRA coverage — and it is ending.
• Your Medicare Advantage plan leaves. It exits Medicare, stops serving your area, or you move away, and you return to Original Medicare.
• The trial right. You joined Medicare Advantage when first eligible at 65 and, within the first year, switch to Original Medicare. This one opens any Medigap policy sold in your state. A mirror-image right covers someone who dropped Medigap to try Advantage for the first time and leaves within a year.
• Your Medigap insurer fails, misled you, or broke the rules.

(Most of these rights cover Plans A, B, D, and G, plus C or F for people eligible before 2020; the trial right at 65 opens any policy.)

A few states go further. New York requires insurers to accept a Medigap application any time of year, with no denial and no premium difference for health. (New York Department of Financial Services.) California gives existing policyholders 60 days after each birthday to switch to a policy with the same or lesser benefits, no medical screening. (California Department of Insurance.) Several other states have their own versions; the federal window is the floor.

The Fine Print

• Plans C and F are closed to newcomers. Since January 1, 2020, a Medigap policy that covers the Part B deductible cannot be sold to anyone newly eligible — in practice, anyone who turned 65 on or after that date. People eligible earlier can still buy and keep them; Plans D and G are the same policies minus the deductible. (42 U.S.C. §1395ss(z); Medicare.gov, compare plan benefits.)
• Plan G and Plan N. Plan G covers everything Plan F does except the Part B deductible. Plan N also leaves the deductible to you, adds copayments for some office and emergency-room visits, and does not cover Part B excess charges. (Medicare.gov, compare plan benefits.)
• That deductible is $283 in 2026, up $26 from $257 — the entire on-paper difference between Plan F and Plan G. A Plan G holder pays the first $283 of Part B costs in a year; the policy picks up from there. (CMS, 2026 Parts A and B fact sheet.)
• No drugs, but guaranteed renewal. Medigap plans sold after 2005 exclude prescription drugs (that is Part D). Once issued, a policy renews every year even if your health changes; premiums can still rise. (Medicare.gov, how Medigap works.)

What This Does Not Mean

None of this says you should buy a Medigap policy. Medicare Advantage or an employer plan may fit a household better; the window governs when the Medigap choice is unconstrained, not whether it is the right one. Nor does a closed window mean you can never buy: guaranteed-issue rights, state rules, and simply passing an insurer’s health questions reopen the door for many people. And the window is not a price guarantee — premiums still vary by company, plan, location, and age, and rise over time. The dollar figures are 2026 amounts; the six months and the 63 days are fixed by rule. Which plan, and when to take Part B, depends on your coverage at work, your health, and your state.

Frequently Asked Questions

Q: When does the Medigap open enrollment window start?

The first day of the month in which you are both 65 or older and enrolled in Part B. It lasts six months and happens once. Part B starting in March 2027 means a window of March through August 2027.

Q: I’m still working at 65 with employer coverage. Do I lose the window?

Not if you delay Part B — the window opens whenever Part B does. The risk is enrolling in Part B at 65 while still on the employer plan: the six months start, expire, and are not repeated when you retire.

Q: Can I buy Medigap after the window closes?

Often, but on the insurer’s terms: in most states it can ask health questions, charge more, or decline you. Federal guaranteed-issue rights — an employer plan ending, an Advantage plan leaving, a first-year exit from Advantage — require the insurer to sell certain plans without health pricing if you apply within 63 days. A few states add year-round or birthday-based rights.

Q: Why can’t I buy Plan F?

Since January 1, 2020, plans that cover the Part B deductible (C and F) cannot be sold to anyone newly eligible for Medicare. Plan G is the same coverage minus that deductible — $283 in 2026.

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General educational information, current as of 2026. Not personalized investment, tax, or legal advice — figures and rules change. For guidance specific to your situation, talk to a qualified professional. See our disclosures.