Anyone whose Medicare Advantage plan is leaving Medicare has a right to buy a Medigap policy, and the window to use it is time-limited. Medicare.gov says the choices are Plan A, B, C, D, F, G, K or L, sold by an insurance company in the person’s state. That is Plan G plus seven others, and the right lasts until 63 days after the Advantage coverage ends.
The timing matters more this fall than most years. Medicare Market Insights counts 3,156,598 people in individual Medicare Advantage plans that are being terminated for 2027, and for many of them coverage ends on December 31, 2026.
The question for those members is which option fits: a different Advantage plan, or Original Medicare with a Medigap policy and a drug plan. The Medigap right applies only to the second route, and it is spelled out on the Medicare.gov Medigap timing page.
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How long does the Medigap right last?
Medicare.gov sets two edges on the window. It opens 60 days before the date the Medicare Advantage coverage ends, and it closes no more than 63 days after that date. For a plan that ends on December 31, 2026, that works out to a window from November 1, 2026 through March 4, 2027.
Medicare.gov adds that the rights may last an extra 12 months in certain circumstances, without spelling out each one. A member who thinks the extension applies should ask Medicare or the Medigap insurer before counting on it, and should treat March 4, 2027 as the working deadline. Applications can go in from November 1, while a policy cannot take effect before the Advantage plan ends on December 31.
Who gets the right, and who does not?
The right depends on what the member does next. Medicare.gov says the person has this right only by switching to Original Medicare, not by joining another Medicare Advantage plan. Someone who picks a replacement Advantage plan does not use it, and the window then passes unused, because Medigap pays alongside Original Medicare and does not work with an Advantage plan.
Medigap coverage also cannot start until the Medicare Advantage plan coverage ends. That is why the 60 days before the end date are useful for applying and lining up the policy, while the start date waits until the old plan has actually stopped.
A person who does nothing during the yearly Open Enrollment Period, which runs October 15 through December 7 according to Medicare.gov, and does not join another Medicare Advantage plan, is automatically enrolled in Original Medicare, the page says. The Medigap window still counts from the day the Advantage coverage ends.
What happens outside the window?
Medicare.gov is direct about the cost of missing it: “there’s no federal guarantee that an insurance company will sell you a Medigap policy.” The page also says a policy bought outside the protected window may cost more because of past or present health problems.
The page tells members to keep any letters, notices, emails or claim denials from the Medicare Advantage plan. That paperwork is the proof that coverage ended, and an insurer may want to see it when a Medigap application arrives.
There is one more check for anyone shopping. The page notes that the plan letters apply to policies sold in the member’s own state, so the company list, the prices and the plan letters on offer will differ from one state to the next. Prices for the same plan letter differ by company, so a side-by-side comparison of quotes comes before any application.
Leaving Medicare Advantage before December 31?
The stake is the 63-day cutoff. A member whose plan ends December 31, 2026 and who misses March 4, 2027 loses the federal right to buy a Medigap policy, and the price can rise with health problems.
The 2027 Medicare Open Enrollment Decision Kit covers Medigap guaranteed-issue rights when a Medicare Advantage plan leaves or a member returns to Original Medicare, with a call script for the conversation with the insurer. It also includes the Open Enrollment calendar, which puts the December 7 end of open enrollment and the Medigap window on one page.
Get the Medigap rights guide and call script in the 2027 Medicare Open Enrollment Decision Kit →
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This article was produced with AI assistance and edited for accuracy against the sources linked above.
