Goodsurance

Enrollment & timing

Federal Medigap Enrollment Window Is Six Months. After That, State Rules Vary Widely, KFF Finds.

A KFF issue brief published the day before open enrollment opens maps when Medicare beneficiaries have a legal right to buy Medigap without medical underwriting, and where that right runs out.

By the Goodsurance editorial teamOctober 14, 2026

Federal law grants Medicare beneficiaries who enroll in Part B at age 65 a single six-month open enrollment window during which any Medigap insurer must sell them a policy without reviewing their medical history. Once that window closes, most states allow insurers to apply medical underwriting, which can result in denial or higher premiums for people with pre-existing conditions.

A KFF issue brief published October 13, 2026 maps out where protections exist beyond that initial window, a question that carries particular weight as Medicare's annual open enrollment period begins October 15.

You have six months to buy Medigap without health questions. After that, your state determines whether you still have a path in.

Federal rules also create guaranteed issue rights for certain qualifying events, including losing employer retiree coverage, leaving a Medicare Advantage plan during a trial period, or having a Medicare Advantage plan exit the market. Thirty-seven states extend qualifying-event protections beyond the federal floor.

Four states, Connecticut, Massachusetts, Maine, and New York, require insurers to sell Medigap to enrollees age 65 and older at any time, regardless of health history. Minnesota added an annual guaranteed issue window for enrollees ages 65 to 70 in August 2026, becoming the most recent state to expand those protections.

In 38 states, Medicare beneficiaries under age 65 who qualify due to a disability also receive a protected initial enrollment window, though coverage requirements differ by plan type.

The analysis is relevant for people considering a switch from Medicare Advantage to Original Medicare during open enrollment. In most states, a person who missed the initial Part B enrollment window and has a significant health history has no guaranteed path to Medigap, a gap the KFF brief documents across all 50 states and the District of Columbia.

In plain words

When you first sign up for Medicare Part B at age 65, you have six months to buy any Medigap plan. During that time, companies must sell to you, even if you have health problems.

After that window closes, most states let companies check your health history. They can say no if you have certain conditions.

There are some exceptions. If you lose job-based insurance, or if your Medicare Advantage plan shuts down, you may get another chance to buy Medigap. Thirty-seven states have extra rules for situations like those.

Four states go further: Connecticut, Massachusetts, Maine, and New York let you buy Medigap at any time, no matter your health. Minnesota added a yearly open window for people ages 65 to 70, starting in August 2026.

Most states also give people under 65 who have Medicare due to a disability a protected window to get Medigap when they first sign up.

KFF published a review of all these rules on October 13, one day before Medicare's fall shopping season opens on October 15. People who want to switch from Medicare Advantage to regular Medicare and add a Medigap plan should check their state's rules first.

Understand the basics first

Source: KFF
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