Medicare Supplement Open Enrollment: 2026 Dates & Rules

The Medigap open enrollment period is a federally protected enrollment window that gives every eligible beneficiary the right to buy a Medicare Supplement policy without health-based barriers. This window is separate from the Medicare Annual Enrollment Period and applies only to Medigap, not to Medicare Advantage or Part D drug plans.   

Medigap open enrollment gives beneficiaries a guaranteed right to buy coverage regardless of medical history, which is a right that ends when the window closes and doesn't resume automatically.

The single governing eligibility condition for Medigap open enrollment is enrollment in both Medicare Part A and Medicare Part B. The open enrollment right is automatic and doesn't require a separate application. The window begins on its own the moment both Part A and Part B enrollment conditions are met at age 65.   

• Adults turning 65 who enroll in Part B for the first time.
• Adults under 65 who receive Medicare due to a qualifying disability, in states that require insurers to offer Medigap to under-65 enrollees. Federal law doesn't require insurers to sell Medigap to under 65 Medicare beneficiaries, but some states do mandate it.
• Adults who delayed Part B because they had employer coverage and are now enrolling in Part B for the first time.
• Retirees who are enrolling in both Part A and Part B simultaneously at age 65 without a prior Medicare enrollment.

The Medigap open enrollment period starts on the first day of the month in which you turn 65 and are enrolled in Medicare Part B, and runs for exactly six months. The window is not tied to a calendar year and is individual to each beneficiary. It moves with your Part B start date, not a fixed annual schedule.

The most common point of confusion is that beneficiaries who delay Part B enrollment because they have employer coverage begin their Medigap open enrollment when Part B starts, not at age 65.

During that six-month window, no insurer can ask about your health conditions, charge more because of pre-existing conditions or reject your application. Because every insurer must accept you regardless of health history, price becomes the only variable that matters when comparing the best Medicare Supplement plans in your state.

Medigap open enrollment comes with four specific rights that don't resume after the window closes unless a qualifying life event triggers a separate guaranteed issue right, a federally protected window during which insurers must accept you regardless of health. The four rights include no medical underwriting, day-one coverage for pre-existing conditions, access to any plan letter the insurer sells and the freedom to choose any insurer in your state on price alone. All four apply for the full six months and lapse when the window ends.

After the six-month Medigap window closes, federal law no longer requires insurers to sell you a Medigap plan and most states do not fill that gap with their own guaranteed access rules. Only Connecticut, Massachusetts, Maine, New York and Washington, require year-round guaranteed issue, where insurers must accept any eligible applicant at any time regardless of health. In the remaining states, the insurer decides whether to accept your application and at what price.

Source: Centers for Medicare and Medicaid Services (CMS). State-specific guaranteed issue rules vary and are subject to change. Confirm current rules with your State Health Insurance Assistance Program (SHIP) counselor or your state insurance commissioner.   

For beneficiaries who already have Medicare Advantage and are considering switching from Medicare Advantage to a Medigap plan, a guaranteed issue right may apply depending on how long you have been enrolled and why you are leaving.

Federal law creates a separate set of guaranteed issue rights triggered by specific life events. These rights restore the protections of Medigap open enrollment for a limited period, typically 63 days from the triggering event. The 63-day clock starts on the date coverage ends or the date you receive written notice that coverage will end, whichever comes first.

Source: Centers for Medicare and Medicaid Services (CMS). Guaranteed issue rights are federally defined and apply in all states. State laws may provide additional triggers beyond those listed here.

The 6-month Medigap window runs from the first day of your Part B enrollment month through the last day of the sixth calendar month. If Part B begins March 1, the open enrollment window runs through August 31. Applications submitted before the window closes are covered by open enrollment rules even if the insurer takes additional time to process and issue the policy.

Yes. The Medicare Part B premium is separate from the Medigap premium and is paid directly to the federal government. The 2026 standard Part B premium is $202.90 per month. Medigap premiums for the same plan letter can differ by hundreds of dollars per year depending on the insurer and pricing method, which is why comparing quotes before your window closes matters.

Federal law permits all three Medigap pricing methods and state law determines which are available where you live.Community-rated plans, where every enrollee pays the same premium regardless of age, often cost more at 65 but don't increase just because you get older. Attained-age plans are cheaper at enrollment and increase annually as you get older. The pricing method is a long-term cost decision, not a monthly premium comparison.

State law determines which pricing methods are available. Some states require community rating for all Medigap plans. Confirm available methods with your state insurance commissioner or SHIP counselor. 

The pricing method an insurer uses is one reason why the top-rated Medicare Supplement insurers do not always have the lowest starting premium. A community-rated plan with a higher monthly cost at 65 can be the more affordable choice at 80, which is why evaluating long-term cost alongside current premium matters during your open enrollment decision.

Your Medigap open enrollment window is the only time you are guaranteed access to any Medicare Supplement plan at standard rates, with no health questions asked. Plan G covers the widest range of Original Medicare cost-sharing for most new enrollees. Factor in the pricing method before you commit. An attained-age plan that's cheap at 65 can become costly by 80. Apply within your six-month window. Miss the window and you may not have guaranteed access again. My recommendation: apply within the first month of your open enrollment window. Premiums for the same plan letter can vary by hundreds of dollars per year across insurers and you want time to compare before locking into an attained-age plan you'll pay more for every year after 65.

The following questions cover common points of confusion about Medigap enrollment timing, switching rules, state-level differences and plan selection: