What Part C Medicare Coverage Is

Part C, also called Medicare Advantage, is an alternative way to receive your Medicare benefits. Instead of using Original Medicare (Part A and Part B), you enroll in a private insurance plan that contracts with Medicare. That private plan becomes responsible for covering the same services that Original Medicare covers — hospital care, doctor visits, and medical equipment — but often with different costs, networks, and rules.

Part C plans are not run by the government. They are run by insurance companies like UnitedHealthcare, Humana, Anthem, and others. You still pay your Part B premium to Medicare, but you also pay the plan's premium (which may be zero dollars) and you use that plan's doctors and hospitals instead of any provider who accepts Medicare.

The main trade-off is this: Part C plans often cost less out of pocket than Original Medicare, but they limit which doctors you can see and may require you to get permission before certain procedures. Original Medicare lets you see any doctor who accepts Medicare anywhere in the country. Part C does not.

Key Takeaways

  • Part C is sold by private insurance companies and replaces Original Medicare — you cannot have both at the same time.
  • Most Part C plans include prescription drug coverage (Part D) built in, whereas Original Medicare requires a separate Part D plan.
  • Part C plans have networks of doctors and hospitals; seeing an out-of-network provider usually costs more or is not covered.
  • Part C plans often include dental, vision, and hearing benefits that Original Medicare does not cover.
  • You can switch between Part C and Original Medicare only during the annual enrollment period (October 15 to December 7) or if you have a may have access to life event.

How Part C Plans Work

When you enroll in a Part C plan, you are signing a contract with that insurance company, not with Medicare directly. The insurance company receives a monthly payment from Medicare for each member, and in return, it must cover all the services that Original Medicare covers. This is called a "capitated" payment — Medicare pays the plan a set amount per person per month.

You choose a primary care doctor from the plan's network. For most services, you see that doctor first, and the doctor refers you to specialists within the network. If you see a doctor outside the network without a referral, you pay more or the visit may not be covered at all. Some plans are HMOs (Health Maintenance Organizations), which are stricter about networks. Others are PPOs (Preferred Provider Organizations), which allow you to see out-of-network doctors but at a higher cost.

Part C plans must cover everything Original Medicare covers. But they can charge different copays and coinsurance amounts than Original Medicare does. For example, one plan might charge $15 for a doctor visit and another might charge $40. You need to read each plan's details to know what you will pay.

What Part C Covers

Part C must cover all the same services as Original Medicare: hospital stays (Part A), doctor visits and outpatient care (Part B), and medical equipment like wheelchairs and oxygen. Part C plans also set an annual out-of-pocket maximum — once you reach that limit, the plan pays 100% of covered services for the rest of the year. Original Medicare has no out-of-pocket maximum.

Most Part C plans include prescription drug coverage (Part D) at no extra cost. If you enroll in a Part C plan, you do not need to enroll in a separate Part D plan. However, you should check whether the plan covers the specific medications you take, because formularies (the list of covered drugs) vary by plan.

Many Part C plans also cover services that Original Medicare does not: dental cleanings and exams, vision exams and eyeglasses, hearing exams and hearing aids, fitness programs, and transportation to medical appointments. These "extra benefits" vary widely by plan and by region. Some plans offer them; others do not.

Part C Costs and How They Differ from Original Medicare

Part C plans have four types of costs: the monthly premium, the annual deductible, copays for each visit or service, and coinsurance (a percentage of the cost you pay). Many Part C plans have a $0 monthly premium, meaning you pay only your Part B premium to Medicare and nothing extra to the plan. But you will pay copays and coinsurance when you use services.

Original Medicare has no network — you can see any doctor who accepts Medicare. But you pay 20% coinsurance for most services after you meet the deductible, and there is no annual cap on what you pay out of pocket. Many people with Original Medicare buy a separate Medigap policy to cover that coinsurance.

Part C plans cap your out-of-pocket spending. In 2024, the maximum out-of-pocket limit for Part C plans ranges from about $4,500 to $8,000 per year, depending on the plan. Once you hit that limit, the plan pays everything. This can make Part C cheaper if you use a lot of medical services, but more expensive if you use very few.

When You Can Enroll in Part C and When You Can Switch

You can enroll in Part C when you first become may be able to access for Medicare (usually at age 65) or during the Annual Enrollment Period, which runs from October 15 to December 7 each year. Changes take effect January 1. You can also enroll in Part C if you have a may have access to life event — such as moving out of your plan's service area, losing employer coverage, or becoming may be able to access for Medicaid — which gives you a 60-day window to enroll.

If you are already in a Part C plan and want to switch to a different Part C plan, you can do so during the Annual Enrollment Period. If you want to switch from Part C back to Original Medicare, you can also do so during the Annual Enrollment Period, but you should enroll in a Part D plan and a Medigap policy at the same time, because you will not have drug coverage or the extra protection that Medigap provides.

If you enroll in Part C after your initial may be able to access period and then want to switch to Original Medicare later, you may face a late enrollment penalty on your Part D premium if you do not enroll in a Part D plan when you leave Part C. The penalty is 1% of the national average Part D premium for each month you were without creditable drug coverage.

Part C Networks and Finding Doctors

Each Part C plan has a network of doctors, hospitals, and other providers. Before you enroll, you should check whether your current doctors are in the plan's network. Most plans publish their network on their website, or you can call the plan and ask. If your doctor is not in the network, you will need to choose a new primary care doctor or pay out-of-network rates.

Part C plans are required to have a service area — a geographic region where the plan operates. If you move outside the service area, you may no longer be able to use that plan. Some plans cover emergency care and urgent care outside the service area, but routine care usually must be within the network. If you move, you should contact your plan to find out whether you can stay enrolled or whether you need to switch.

HMO plans are generally more restrictive than PPO plans. In an HMO, you must use network providers and you need a referral from your primary care doctor to see a specialist. In a PPO, you can see out-of-network providers without a referral, but you pay more. Some plans are regional PPOs, which cover a larger geographic area than HMOs but still have networks.

Questions to Ask Your Doctor and When to Seek Care

Before you enroll in a Part C plan, ask your current doctor whether they are in the plan's network and whether they recommend the plan. Ask your doctor about any specialists you see regularly and whether those specialists are also in the network. If your doctor is not in the network, ask whether they can recommend another doctor in the plan who provides similar care.

Once you are enrolled in a Part C plan, ask your doctor's office about copays and whether you need a referral for specialists. Ask whether the plan covers the medications you take and whether there are any restrictions on getting them. If you are considering a procedure, ask your doctor whether the plan requires prior authorization — many Part C plans require you to get permission from the plan before certain surgeries or treatments.

Seek care when ready if you have chest pain, difficulty breathing, signs of stroke (facial drooping, arm weakness, speech difficulty), severe bleeding, or any other life-threatening symptom. Call 911 or go to the nearest emergency room. Part C plans must cover emergency care, and you do not need permission from the plan to go to the emergency room. After the emergency, ask the hospital to help you understand what the plan will cover.

Frequently Asked Questions

Can I have Part C and Original Medicare at the same time?

No. When you enroll in Part C, you are automatically disenrolled from Original Medicare. If you later switch back to Original Medicare, you must enroll in a Part D plan and consider a Medigap policy to cover coinsurance and deductibles.

What happens if I move and my Part C plan does not serve my new area?

You can switch to a different Part C plan that serves your new area, or you can switch to Original Medicare. You have 60 days from the date you move to make the change. Contact your current plan or Medicare to find out which plans are available in your new location.

Do Part C plans cover out-of-network doctors?

It depends on the plan type. HMO plans do not cover out-of-network care except in emergencies. PPO plans cover out-of-network care but charge higher copays or coinsurance. Check your plan's details to see what you would pay for out-of-network care.

If I switch from Part C to Original Medicare, do I need a Medigap policy?

You do not need a Medigap policy, but it is often a good idea. Original Medicare covers 80% of most services after the deductible, and you pay 20%. Medigap covers some or all of that 20%. Without Medigap, you could face large out-of-pocket costs if you use a lot of medical services.

Can I change Part C plans in the middle of the year?

No, unless you have a may have access to life event such as moving, losing employer coverage, or becoming may be able to access for Medicaid. Otherwise, you can change plans only during the Annual Enrollment Period (October 15 to December 7).