What Medicare Part C Is

Medicare Part C, also called Medicare Advantage, is an alternative way to receive your Medicare benefits. Instead of using Original Medicare (Parts A and B), you join a private insurance plan approved by Medicare. That plan becomes responsible for covering your hospital care, doctor visits, and other services that Original Medicare would cover.

The key difference: Original Medicare is run by the federal government. Part C plans are run by private insurers like UnitedHealth, 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 use that plan's doctors and hospitals.

Part C plans must cover everything Original Medicare covers, but they often add extras — dental, vision, hearing, gym memberships, or prescription drug coverage — that Original Medicare does not. In exchange, you usually have a smaller network of doctors and hospitals, and you may face higher out-of-pocket costs if you use providers outside that network.

Key Takeaways

  • Part C is a private insurance alternative to Original Medicare that must cover all the same hospital and doctor services, but often includes dental, vision, and hearing benefits that Original Medicare does not.
  • You must have both Part A and Part B to join a Part C plan, and you continue paying your Part B premium plus the plan's own premium.
  • Part C plans use networks of doctors and hospitals, and you typically pay more if you see providers outside that network.
  • You can switch to a different Part C plan or return to Original Medicare during the Annual Enrollment Period (October 15 to December 7 each year) or if you have a may have access to life event.
  • Part C plans often include prescription drug coverage built in, unlike Original Medicare, which requires a separate Part D plan.

How Part C Plans Are Structured

Most Part C plans operate as Health Maintenance Organizations (HMOs) or Preferred Provider Organizations (PPOs). An HMO requires you to choose a primary care doctor and get referrals to see specialists; you pay nothing or very little for in-network care, but out-of-network care is usually not covered except emergencies. A PPO lets you see any doctor without a referral, but you pay more for out-of-network providers than in-network ones.

Some plans also offer Private Fee-for-Service (PFFS) options, which work more like Original Medicare but through a private company. These are less common and have different rules about which providers must accept them.

Every Part C plan has a service area — a specific county or region where it operates. You must live in that area to join. Plans change their service areas, doctors, and benefits each year, so you need to check whether your current plan still serves your address and includes your doctors.

What Part C Covers and What It Costs

Part C must cover all services that Original Medicare Part A and Part B cover: hospital stays, doctor visits, lab tests, imaging, outpatient surgery, and preventive care. However, the cost structure is different. Instead of paying a deductible and coinsurance the way you would under Original Medicare, you typically pay a copay (a flat fee like $15 for a doctor visit) or coinsurance (a percentage of the cost).

Out-of-pocket costs vary widely by plan. Some plans have very low premiums but high copays; others charge a higher premium but lower copays. All Part C plans have an out-of-pocket maximum — once you reach it in a calendar year, the plan covers 100 percent of your in-network care for the rest of that year. This maximum varies by plan and by year.

Many Part C plans include prescription drug coverage (Part D) at no extra cost, though some do not. If your plan does not include drug coverage and you take medications, you would need to join a separate Part D plan. Some plans also cover dental cleanings and exams, vision exams and eyeglasses, hearing exams and hearing aids, or fitness programs — but the scope and quality of these extras differ significantly between plans.

How to Enroll in Part C

You can join a Part C plan only during certain times. The main enrollment window is the Annual Enrollment Period (AEP), which runs from October 15 to December 7 each year. Changes take effect January 1. You can also join during your initial enrollment period when you first turn 65 and become may be able to access for Medicare.

If you have a may have access to life event — such as moving out of your plan's service area, losing other health coverage, or experiencing a death in your family — you may be able to join or switch plans outside the annual window. You typically have 60 days from the event to make a change.

To enroll, you can visit Medicare.gov, call 1-800-MEDICARE, visit your local Social Security office, or work with a licensed insurance agent or broker who represents Part C plans. You will need your Medicare card and Social Security number. The plan will confirm your enrollment and send you a member ID card, usually within two weeks.

Part C Versus Original Medicare: When Each Makes Sense

Part C is often a better choice if you want dental, vision, or hearing coverage; if you prefer predictable copays over deductibles and coinsurance; or if you are willing to use a limited network of doctors. It can also cost less in premiums if you find a plan with a zero-dollar premium.

Original Medicare may be better if you travel frequently or live part of the year in different states, because Original Medicare works nationwide and Part C does not. Original Medicare is also better if you have a doctor or specialist you want to see and that provider does not accept your Part C plan. If you have both Medicare and Medicaid (dual may be able to access), some Part C plans are designed for you, but Original Medicare may offer more flexibility in some states.

You do not have to stay with the same plan forever. You can switch to a different Part C plan or return to Original Medicare during the Annual Enrollment Period each fall, so if your situation changes or your plan stops meeting your needs, you have an annual opportunity to change.

Common Mistakes to Avoid

One frequent mistake is assuming your current doctor is in your plan's network without checking. Networks change every year, and a doctor who was in-network last year may not be this year. Before you enroll, call the plan or check its website to confirm that your primary care doctor, any specialists you see regularly, and your preferred hospital are all in-network.

Another mistake is not comparing plans side by side. Two plans may have similar premiums but very different copays, out-of-pocket maximums, and extra benefits. Use the Medicare Plan Finder tool on Medicare.gov to see all available plans in your area, their costs, and their benefits in one place.

A third mistake is forgetting to check whether your plan covers your current medications at the cost you expect. If your plan includes Part D, review the formulary (the list of covered drugs) to see whether your medications are covered and at what tier, because the copay can vary from $5 to $50 or more depending on the drug and the plan.

How to Switch or Leave a Part C Plan

During the Annual Enrollment Period (October 15 to December 7), you can switch to a different Part C plan, join Original Medicare, or make other changes to your coverage. You do not need permission or a reason — you straightforward enroll in the new plan, and your old plan coverage ends on December 31.

If you want to leave Part C and return to Original Medicare, you should also join a Part D prescription drug plan at the same time, because if you go without Part D coverage when you are may be able to access, you may face a penalty later. The same applies if you switch from one Part C plan to another: make sure the new plan's drug coverage (if any) meets your needs, or join a separate Part D plan.

If you move out of your plan's service area, you can change plans when ready rather than waiting for the annual enrollment period. You will need to provide proof of your move, such as a lease or utility bill showing your new address.

Frequently Asked Questions

Do I have to join a Part C plan, or can I stay on Original Medicare?

No, you do not have to join Part C. You can stay on Original Medicare and add a separate Part D prescription drug plan and a Medigap supplemental plan if you want. Part C is optional — it is straightforward an alternative way to receive your Medicare benefits.

What happens if I need care outside my Part C plan's service area?

Most Part C plans do not cover non-emergency care outside their service area. If you travel frequently or spend part of the year in another state, Original Medicare may be a better fit because it works nationwide. Some Part C plans offer limited out-of-area coverage, so check your plan's rules before you travel.

Can I have both Part C and a Medigap plan?

No. If you have a Part C plan, you cannot also have a Medigap supplemental plan — it is one or the other. Part C plans are designed to replace Original Medicare, so adding Medigap would be redundant. If you leave Part C and return to Original Medicare, you can then join a Medigap plan.

What if my Part C plan drops out of Medicare or stops serving my area?

If your plan leaves Medicare or stops serving your county, you receive a notice from the plan and from Medicare. You then have a special enrollment period to switch to a different Part C plan or return to Original Medicare without waiting for the annual enrollment period. You should act within the timeframe given in the notice.

Do Part C plans cover long-term care or nursing home stays?

Part C covers skilled nursing facility stays (short-term rehabilitation after a hospital stay) the same way Original Medicare does. It does not cover long-term custodial care in a nursing home or assisted living. For that type of care, you would need a separate long-term care insurance policy or to pay out of pocket.