Leaving Medicare Advantage Takes One Phone Call. Getting the Medigap Policy That Makes Leaving Affordable Can Require Medical Underwriting.

A 71-year-old Medicare Advantage member watches his longtime cardiologist leave the plan’s network. During the Medicare Advantage Open Enrollment Period, he decides he has had enough. He can return to Original Medicare effective the first of the following month and regain access to any doctor who accepts Medicare. Then he calls a Medigap broker about Plan G.

The questions start almost immediately: heart disease, medications, hospitalizations, procedures. Two prescriptions taken together are enough for one carrier to decline him. Another will not take the cardiac history. Suddenly, leaving Medicare Advantage was the easy part. The coverage he wants on the other side is where the door gets narrower.

Medicare Advantage Has an Exit. Medigap Has an Entrance Exam of Its Own

Each fall, from October 15 through December 7, Medicare beneficiaries can leave Medicare Advantage and return to Original Medicare for January 1. People already enrolled in Medicare Advantage get another opportunity from January 1 through March 31, when they can make one change, including a move back to Original Medicare. Medigap follows a different calendar.

The federal Medigap open enrollment period lasts six months beginning when someone is 65 or older and enrolled in Medicare Part B. During that protected window, insurers cannot reject an applicant or charge more because of health.

Years later, that protection is usually gone. In most states, someone applying for a new Medigap policy can face medical underwriting unless a guaranteed-issue right or stronger state rule applies. That is the mismatch: Medicare may let him leave Advantage without asking about his heart. The Medigap insurer she needs afterward may care very much about it.

Original Medicare Leaves the 20% Problem Behind

Original Medicare gives him wider provider access, but it does not come with an annual out-of-pocket ceiling. In 2026, Part B carries a $283 deductible. After that, beneficiaries generally owe 20% of the Medicare-approved amount for covered physician services, outpatient procedures and other Part B care.

For someone with a cardiac history, an uncapped percentage is not an abstract concern. Specialist visits, imaging and outpatient procedures can keep generating coinsurance through the year. Part A brings its own cost sharing, including a $1,736 hospital deductible per benefit period in 2026. Plan G covers many of those gaps, leaving the beneficiary responsible for the Part B deductible. That is why getting approved for the supplement can be every bit as important as getting out of the Advantage plan.

The Exceptions Matter More Than People Realize

Federal guaranteed-issue rights can reopen Medigap in specific circumstances. If a Medicare Advantage plan leaves Medicare, stops serving an enrollee’s area or the member moves outside its service area, federal protections may allow the person to buy certain Medigap plans without medical underwriting.

Trial rights can help too. Someone who joined Medicare Advantage when first eligible at 65 may have protection if returning to Original Medicare within the first year. A person who dropped an existing Medigap policy to try Medicare Advantage for the first time can also have a limited path back.

Those are defined exceptions, not a general promise that anyone leaving Medicare Advantage can buy Medigap afterward. State law can provide additional opportunities, which makes the ZIP code almost as important as the medical history. The cost and coverage traps that can surface during a switch are among those we mapped in a free Medicare guide here.

Secure the Landing Before Leaving the Plan

Someone thinking about moving back to Original Medicare should put the pieces in the right order:

• Confirm that the enrollment period or Special Enrollment Period actually allows the Medicare Advantage exit and when Original Medicare will begin.
• Apply for Medigap before giving up existing coverage when underwriting is required, and wait for a written approval rather than assuming a quote means acceptance.
• If Medigap is unavailable or prohibitively expensive, compare the cost and provider access of staying in Medicare Advantage or moving to another Advantage plan before making the switch.

The attraction of Original Medicare is freedom to see almost any provider who accepts it. The catch is that flexibility does not automatically come with protection from the bills Medicare leaves behind. Before walking out of Medicare Advantage, make sure the coverage you expect to meet you on the other side is actually there.

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