Medigap vs. Medicare Advantage: what caregivers should know

Two paths, not two plans

Medigap (Medicare Supplement Insurance) is extra insurance from a private company that helps pay your share of costs in Original Medicare, like the 20% coinsurance. You can only buy Medigap if you have Original Medicare. With Original Medicare, drug coverage comes from a separate Medicare drug plan (Part D) that you can join.

A Medicare Advantage plan (Part C) is a different way to get Medicare from a private plan. It must cover all medically necessary services Original Medicare covers, may add extras like some vision, hearing, and dental, and most include drug coverage. You can't buy Medigap to cover costs in a Medicare Advantage plan.

Our Medicare basics page compares the two side by side.

Doctors, referrals, and approvals

With Original Medicare, your parent can see any doctor or hospital that takes Medicare, anywhere in the U.S., and in most cases needs no referral or prior approval.

With Medicare Advantage, they may need to use doctors in the plan's network and service area for non-emergency care. Some plans cover out-of-network care at a higher cost. They may need a referral to see a specialist, or approval in advance (prior authorization) for some services.

How the costs work

Original Medicare has no yearly limit on what you pay out of pocket. Medigap helps pay your share of those costs, for a monthly premium. Medigap policies are standardized by letter (Plans A–D, F, G, and K–N in most states): plans with the same letter have the same basic benefits, and price is the only difference between companies.

Medicare Advantage plans have a yearly limit on what you pay for covered services; after you reach it, you pay nothing more for covered services that year. You still pay the Part B premium, and some plans charge their own premium. Copays and limits vary by plan, so compare the 2027 numbers in each plan's documents.

Travel

Inside the U.S., Original Medicare works with any provider that takes Medicare, while a Medicare Advantage plan may only cover non-emergency care in its network and service area. Outside the U.S., Original Medicare and Advantage plans generally don't cover care. Some Medigap policies cover emergency care abroad, and some Advantage plans offer it as an extra benefit.

Switching back later: the part families miss

Medicare Open Enrollment (October 15 to December 7, 2026, for coverage starting January 1, 2027) lets you move between Original Medicare and Medicare Advantage. It does not give anyone a right to buy Medigap.

Federal law gives a one-time, 6-month Medigap Open Enrollment Period, starting the first month someone has Part B and is 65 or older. During it, a company can't turn them down or charge more for health problems. It does not repeat every year.

After that window, an insurance company can deny a Medigap policy based on health questions (medical underwriting), or charge more. So someone who leaves Medigap for Medicare Advantage may not be able to get Medigap back later.

There are exceptions, called guaranteed issue rights. They include a “trial right”: if your parent joined Medicare Advantage when first eligible for Medicare and wants to switch to Original Medicare within the first year, or dropped a Medigap policy to try Medicare Advantage for the first time and has been in the plan less than a year. Other situations include an Advantage plan leaving the area or the person moving out of it. Some states give more rights than federal law — check with your State Insurance Department.

What neither one pays for: long-term care

Medicare does not pay for long-term custodial care — help with bathing, dressing, and other daily activities — and Medicare says most health insurance, including Medigap, doesn't either. That is true in a nursing home or at home.

Part A may cover a short skilled nursing home or rehab stay (up to 100 days) after a hospital stay when skilled care is needed. Home health is covered only for part-time or intermittent skilled care for someone who is homebound, and never 24-hour care. Medicare Advantage plans usually don't help pay for nursing home care unless the home has a contract with the plan.

Medicaid may pay for long-term care for people who meet their state's rules. Read what Medicare and Medicaid actually pay for, and compare nursing homes or home health agencies near you.

Checklist

• Ask your parent which doctors and hospitals they must keep.
• Check whether they are still in their 6-month Medigap Open Enrollment Period.
• Before dropping Medigap, ask whether they could get it back later.
• Compare drug coverage for every prescription under both paths.
• Plan separately for long-term care; neither path pays for it.
• Call your state's SHIP or State Insurance Department about state rules.