Medigap vs. Medicare Advantage: How to Choose
Medigap and Medicare Advantage solve the same problem, capping your out-of-pocket costs, in very different ways. Here’s how they compare, and why timing matters.
By Boris Sorto, Healthcare Advocate · Updated August 26, 2026
Medigap (Medicare Supplement Insurance) works alongside Original Medicare to cover leftover costs like deductibles and coinsurance, for a monthly premium, with no provider network. Medicare Advantage replaces Original Medicare with a private plan that bundles extra benefits and drug coverage, usually for a lower premium, but within a network. You can’t have both at once.
Side-by-side comparison
| Medigap | Medicare Advantage | |
|---|---|---|
| Works with | Original Medicare only | Replaces Original Medicare |
| Provider network | None; any provider accepting Medicare | Plan’s network |
| Monthly premium | Usually higher | Often lower, sometimes $0 |
| Drug coverage | Not included; needs separate Part D | Usually included |
| Extra benefits | Not included | Often included (dental, vision, hearing) |
| Best window to enroll | 6 months after Part B starts, at 65 | Any AEP or IEP |
Why timing matters for Medigap
Unlike Medicare Advantage, which you can generally join or leave every AEP, Medigap has a one-time window with the strongest consumer protections: the 6 months starting when you’re both 65 and enrolled in Part B. Buy during that window, and insurers can’t deny you or charge more based on health conditions. Miss it, and insurers in most states can use medical underwriting, which matters a great deal if you have an existing health condition.
Approaching this decision point? A Medicare Annual Checkup can walk through the timing and the trade-offs before your window closes.
Frequently asked questions
Can I have both Medigap and Medicare Advantage?
No. A Medigap policy only works alongside Original Medicare. It’s illegal for someone to sell you a Medigap policy if you’re enrolled in Medicare Advantage.
Why does timing matter so much for buying Medigap?
During your Medigap Open Enrollment Period (the 6 months starting when you’re 65 and enrolled in Part B), insurers must sell you a policy regardless of health conditions. Outside that window, insurers can generally use medical underwriting to deny you or charge more.
Written by Boris Sorto
Bilingual Healthcare Advocate, formerly with Humana’s Medicare operations. More about Boris →