Seniors who drop a Medicare Advantage plan for Original Medicare can find the door to Medigap closed. Medicare.gov says there is no federal guarantee that an insurance company will sell a Medigap policy outside a short list of protected situations, and a company can turn down an applicant over health. Original Medicare on its own also has no yearly limit on out-of-pocket costs, unless the person has supplemental coverage.
Medigap, also called Medicare Supplement Insurance, is private insurance sold in each state that helps pay costs Original Medicare leaves behind, according to the Medigap guide from Medicare and state insurance regulators. The catch is timing. The right to buy a policy without health questions comes only in certain windows.
Who has a guaranteed right to buy Medigap
Medicare.gov names the situations. When a Medicare Advantage plan is leaving Medicare, or no longer covers the area where someone lives, that person can buy any Medigap Plan A, B, C, D, F, G, K or L sold in the state. The application window opens 60 days before the Advantage coverage ends and closes no more than 63 days after.
That leaves a plain test for anyone on an Advantage plan. A plan that is ending or leaving the area may carry a guaranteed right. A plan that is staying in business, with no such trigger, means the application goes through the insurer’s health questions, and the company can say no.
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One condition applies. The right exists only when the person moves to Original Medicare rather than joining another Medicare Advantage plan, and the Medigap coverage cannot start until the Advantage coverage ends. The guide adds that moving out of the plan’s service area or a significant change in the plan’s network can also open the door, and that the rights may last an extra 12 months in certain circumstances.
A second route is the trial right. Someone who joined a Medicare Advantage plan when first eligible for Medicare at 65 can switch to Original Medicare within the first year and buy any Medigap policy sold in the state. Separately, Medigap has a one-time six-month open enrollment period that starts the first month a person is 65 or older and enrolled in Part B.
The dates that matter when a plan ends
A plan that does not renew sets its own clock. Medicare’s special enrollment page says the window to switch runs from December 8 to the last day of February of the following year. Anyone who does not join another Medicare Advantage plan before the current one ends is enrolled in Original Medicare.
That automatic move is exactly when the Medigap window matters. The 63-day clock runs from the day the Advantage coverage ends, so a plan whose coverage ends December 31, 2026 puts the last day to apply on March 4, 2027. The plan’s termination notice is the simplest proof of when the coverage ended.
Other endings carry other windows. Medicare.gov lists a switch period that starts one month before a contract ends and runs two full months after when Medicare itself ends the plan’s contract, and one that starts two months before and runs one full month after when the plan and Medicare end the contract together. After a move out of a plan’s area, the switch period begins at the move and continues two full months.
Annual open enrollment runs October 15 through December 7, and switching plans during it is allowed. A Medigap guarantee is a separate question, and the triggers above decide it. Questions about a notice can go to 1-800-MEDICARE (1-800-633-4227), the number Medicare.gov gives on that same page.
State law can add protection. The guide says people may have additional rights under state law, and the Medicare.gov timing page says its answers apply only to federal rights. Anyone in that spot can ask the state insurance department whether the state offers more.
What Original Medicare leaves unpaid
The size of the gap explains why the window matters. Medicare.gov’s 2026 cost page lists a $1,736 deductible for each hospital benefit period, then $434 a day for hospital days 61 through 90 and $868 a day for days 91 through 150, which draw on 60 lifetime reserve days. After day 150, the patient pays all costs.
Doctor and outpatient care carry their own costs: a Part B premium of $202.90 a month, a $283 deductible, and usually 20% of the cost of each covered service after that. With no yearly limit, 20% of a large bill stays a large bill. That is why a denied Medigap application matters more than it first sounds.
The open question for each senior on an Advantage plan is which side of that line the situation falls on. The answer turns on dates in the plan’s own notices: when the Advantage coverage ends, and whether the plan is leaving Medicare or simply staying in business.
Thinking about leaving a Medicare Advantage plan for Original Medicare?
Outside those windows, a Medigap application goes through health questions, and an insurer can refuse it. The 63-day clock after an Advantage plan ends starts on the coverage end date, not on the day the notice is opened.
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 insurer. It also holds a cost calculator spreadsheet that compares plans on cost, drugs and doctors, plus the Open Enrollment calendar.
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This article was produced with AI assistance and edited for accuracy against the sources linked above.
