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Before switching from Medicare Advantage to Original Medicare, review your eligibility for Medicare Supplement coverage and coordinate any prescription drug plan.

Two different enrollment periods—and a crucial distinction

Medicare's annual Open Enrollment Period runs from October 15 through December 7, 2026. During that window, eligible beneficiaries can change Medicare Advantage or Part D coverage, or switch between Medicare Advantage and Original Medicare. Changes made during this period generally begin January 1, 2027.

Medigap has a separate enrollment rule. Under federal law, the one-time six-month Medigap Open Enrollment Period begins the first month you are 65 or older and enrolled in Medicare Part B. It does not restart each October 15. During that initial period, insurers generally cannot deny you a Medigap policy they sell because of health conditions.

Important: The ability to leave a Medicare Advantage plan does not, by itself, create a federal right to buy any Medigap policy. If your initial Medigap enrollment period has ended, an insurer may be allowed to use medical underwriting or deny an application unless a guaranteed-issue right or a state protection applies.

When might you have a guaranteed-issue right?

Federal rules provide Medigap protections in specific situations. Two common examples involve a trial right:

  • You joined Medicare Advantage when first eligible for Medicare at age 65 and decide to return to Original Medicare within your first year in that Medicare Advantage plan. A limited right to buy certain Medigap policies may apply.
  • You dropped a Medigap policy to join Medicare Advantage for the first time and return to Original Medicare within 12 months. You may have the right to get your former Medigap policy back if it is still sold, or to buy certain alternatives.

Other guaranteed-issue rights may arise when a Medicare Advantage plan leaves Medicare or stops serving your area, or in certain other qualifying circumstances. These rules are fact-specific; the available Medigap plans and application deadlines depend on which protection applies. Medicare's Medigap eligibility guide can help you identify your situation.

Deadlines can be different from December 7

For several guaranteed-issue situations tied to losing Medicare Advantage coverage, Medicare describes an application window beginning 60 days before the coverage ends and ending 63 days after it ends. Other situations have different rules. Do not assume the annual Medicare enrollment deadline is also your Medigap deadline. Keep plan termination notices and other documentation that may prove a guaranteed-issue right.

States may provide additional protections beyond federal law. Ask your state insurance department or your State Health Insurance Assistance Program (SHIP) about rights where you live. For example, some states provide additional opportunities to change Medigap policies.

Remember prescription coverage and the full cost picture

Medigap policies sold today generally do not include prescription drug coverage. If you move to Original Medicare and want drug coverage, you may need to enroll in a separate Part D plan. Review your prescriptions, pharmacies and enrollment timing so you do not unintentionally create a gap in coverage.

Compare the full financial picture: Original Medicare Part B premiums, potential Medigap premiums, Part D premiums, deductibles, and your expected care. Unlike Medicare Advantage plans, Original Medicare by itself has no annual out-of-pocket maximum for covered Part A and Part B services. A Medigap policy may help with some of those costs, but benefits depend on the policy.

Four questions to answer before changing coverage

  1. Can I buy Medigap? Confirm whether you are within your six-month enrollment period, have a guaranteed-issue right, qualify under state law, or would need underwriting approval.
  2. Which policy and effective date? Verify availability, premium, underwriting requirements, and when the policy can start. Medigap coverage cannot begin while you remain enrolled in Medicare Advantage.
  3. What happens to my prescriptions? Review a stand-alone Part D plan and avoid an unintended coverage gap or late-enrollment issue.
  4. Does the overall coverage fit? Compare your doctors, medications, budget, travel needs, and expected out-of-pocket costs—not just the advertised premium.

Practical next step: Confirm your Medigap options and timing before making a change you may not be able to reverse easily. Ask the insurer for written information about acceptance and effective dates, and do not cancel any existing supplemental coverage without understanding your options.

The Medicare Minute takeaway: Medicare Open Enrollment starts October 15, 2026, but Medigap enrollment rights follow different rules. If you are thinking about leaving Medicare Advantage for Original Medicare, check your eligibility for a supplement and your Part D arrangements before finalizing a switch.
Educational information only. This article summarizes Medicare.gov guidance available as of October 14, 2026. Medigap eligibility, underwriting, guaranteed-issue rights, policy availability and premiums vary by circumstances and state law. This is not legal, financial or medical advice. Medicare Advisors is an independent insurance agency and is not connected with or endorsed by the U.S. government or the federal Medicare program.