Medigap vs. Medicare Advantage: What's the Difference, and Can You Switch Later?
Learning goal: Compare Medigap with Medicare Advantage, and understand why switching from Medicare Advantage back to Original Medicare with Medigap can be hard later.
Short answer
Medigap is extra private insurance that works with Original Medicare to pay your share of costs, like the 20% coinsurance. Medicare Advantage is a private plan that replaces Original Medicare. You generally can't have both. The key catch: outside your one-time Medigap open enrollment, insurers may deny you Medigap or charge more for health problems.
Read to the end to complete this lesson.
On this page
The Fuller Picture
So the first decision at 65 matters. If you start with Medicare Advantage and later want Original Medicare with Medigap, you can switch to Original Medicare during enrollment periods, but buying Medigap then may require medical underwriting, except where a guaranteed issue right or state law applies. Medigap plans are standardized by letter, so Plan G pays the same benefits from any insurer.
Key Takeaways
- Medicare.gov: "Under federal law, you get a 6 month Medigap Open Enrollment Period."
- During it, an insurer can't refuse to sell you a Medigap policy or charge more for pre-existing conditions.
- Outside it, an insurer may deny you a policy if you don't meet its medical underwriting requirements.
- Medigap policies are standardized; the benefits in each lettered plan are the same whichever company sells it.
- Medigap works with Original Medicare, not with Medicare Advantage.
Real-World Example
Walt
Walt joins a Medicare Advantage plan at 65. At 70, after a heart diagnosis, he wants Original Medicare with Medigap to see specialists anywhere. He can return to Original Medicare during an enrollment period, but his Medigap open enrollment ended years ago, and insurers in his state can use medical underwriting. Two deny him. He checks with his SHIP whether he has a guaranteed-issue right.
Common Mistakes
- Picking Medicare Advantage at 65 without knowing switching to Medigap later may be hard.
- Comparing Medigap plans by insurer brand rather than plan letter and price.
- Missing the 6-month Medigap open enrollment.
- Not checking your state's extra Medigap rights.
Interactive Exercise
Before You Choose at 65
Work through these before your Medigap open enrollment ends.
Tick each step as you do it. Your checklist is saved in this browser.
Knowledge Check
Question: Why can it be hard to switch from Medicare Advantage to Original Medicare with Medigap years later?
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- Insurance Preparedness Checklist: Twelve insurance questions worth having an answer to, with a place to learn more about each one you have not looked at yet. No score.
Related Insurance Terms
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Questions to explore next
Questions readers often ask next about this topic:
- Should I choose Medigap or Medicare Advantage?
- When does my Medigap open enrollment end?
- Do I have a guaranteed issue right?
- Which Medigap plan letter fits me?
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The factual claims on this page were checked against these sources. Rules and figures change, so check the source itself if you need to confirm the current version.
- medicare.govGet ready to buy (Medigap) · Medicare.gov (U.S. Centers for Medicare & Medicaid Services)
- medicare.govParts of Medicare · Medicare.gov (U.S. Centers for Medicare & Medicaid Services)
Educational information, not advice: This lesson is for general education only, not legal, financial, or insurance advice. Actual coverage, discounts, and requirements depend on your policy’s wording, your insurer, and the laws of your state. Confirm specifics with your own insurer or a licensed agent before making a decision. Insurpedia does not sell insurance and does not recommend specific insurers. Rules and 2026 figures are from Medicare.gov. Figures change each year, and your situation may differ. For personal help, contact your State Health Insurance Assistance Program (SHIP) or Social Security. Educational information, not advice.