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. 

The core value of Medigap open enrollment is the guaranteed right to purchase coverage regardless of your medical history, a protection that does not automatically continue after the window closes. For a broader overview of how Medicare coverage fits together, including Parts A, B, C and D, that context can help clarify where Medigap fits in the overall structure.

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 does not 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 does not 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.

Your Medigap open enrollment period begins on the first day of the month in which you are both 65 and enrolled in Medicare Part B and runs for exactly six months from that date. The window is not tied to a calendar year. The Medigap open enrollment window is personal to each beneficiary and moves with your Part B start date. The most common source of confusion involves beneficiaries who delay Part B enrollment because they have employer coverage. Those beneficiaries start their Medigap open enrollment when Part B begins, not at age 65. 

During this six-month window, the insurer cannot ask about your health conditions, cannot charge you more because of pre-existing conditions and cannot reject your application. That protection means price becomes the primary variable when comparing the best Medicare Supplement plans available in your state, since every insurer must accept you regardless of your health history.

Medigap open enrollment provides four specific protections that are not available again unless a qualifying life event triggers a separate guaranteed issue right later: no medical underwriting, coverage for pre-existing conditions from day one, access to any plan letter the insurer sells and the right to choose any insurer in your state based on price alone. Each protection applies for the full six-month window and ends when the window closes.

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 a small number of states, including Connecticut, Massachusetts, Maine, New York and Washington, require year-round guaranteed issue. 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 six-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 vary by plan letter, insurer and the pricing method the insurer uses, which is why comparing quotes across multiple insurers during open enrollment is important.

All three Medigap pricing methods are permitted under federal law and state law determines which methods are available in each state. Community-rated plans often cost more at age 65 but are more predictable over time, while attained-age plans start cheaper and increase annually as you age. Choosing a pricing method is a long-term cost decision, not just 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 is the strongest choice for most new enrollees, covering nearly all Original Medicare gaps. Factor in the pricing method before you commit an attained-age plan that is cheap at 65 can become costly by 80. Apply within your six-month window. Waiting puts your guaranteed access at risk.

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