What Medicare Part C Is

Medicare Part C, also called Medicare Advantage, is a way to get your Medicare coverage through a private insurance company instead of through the government's Original Medicare (Parts A and B). The private insurer is paid by Medicare to cover the same hospital and doctor services that Original Medicare covers, but the plan may have different costs, rules about which doctors you can see, and extra benefits.

Part C is optional. You do not have to choose it. If you have Original Medicare, you can stay with it. If you switch to Part C, you can switch back to Original Medicare later during the annual open enrollment period (October 15 to December 7 each year).

Key Takeaways

  • Medicare Part C is sold by private insurance companies and covers the same hospital and doctor services as Original Medicare, but with different costs and rules.
  • Most Part C plans include prescription drug coverage (Part D) and extra benefits like dental, vision, or hearing aids, which Original Medicare does not cover.
  • Part C plans often have lower or no monthly premiums than Original Medicare plus a separate Part D plan, but you pay more when you use services through copays and deductibles.
  • You must see doctors and hospitals in the plan's network, except in emergencies, and you need a referral from your primary care doctor to see a specialist.
  • You can change to a different Part C plan or switch back to Original Medicare once per year during open enrollment.

How Part C Differs From Original Medicare

Original Medicare is run by the federal government. You can see any doctor or hospital that accepts Medicare anywhere in the country. You pay a monthly premium for Part B (doctor visits), and you have a deductible and coinsurance for each service. Prescription drugs are not covered unless you buy a separate Part D plan.

Part C is run by private companies like UnitedHealthcare, Humana, Aetna, and Cigna. You must use doctors and hospitals in the plan's network (except emergencies). Most plans require you to pick a primary care doctor who coordinates your care and gives referrals to specialists. In exchange, many Part C plans charge a lower or zero monthly premium, include prescription drug coverage, and offer extras like dental cleanings or eyeglasses that Original Medicare does not pay for.

The trade-off is that you typically pay more out of pocket when you use services. A Part C plan might charge a $25 copay for a doctor visit instead of the 20% coinsurance you would pay under Original Medicare, depending on the plan and the service.

What Part C Plans Cover and What They Cost

All Part C plans must cover everything Original Medicare covers: hospital stays (Part A), doctor visits and outpatient care (Part B), and preventive services with no copay. Many plans also include Part D prescription drug coverage at no extra premium, though you still pay copays for medications.

Beyond the basics, plans vary widely. Some offer dental coverage (cleanings, fillings, extractions), vision coverage (eye exams, glasses, contact lenses), hearing aid coverage, or fitness benefits. A few plans cover transportation to medical appointments or over-the-counter health items. Read the plan's benefits document to see what is included.

Costs depend on the plan. Most Part C plans have a monthly premium of $0 to $200, though some cost more. You also pay a yearly deductible (often $0 to $500) before the plan starts paying for most services, and then copays or coinsurance for each visit or service. Some plans have an out-of-pocket maximum—a yearly cap on what you pay—after which the plan covers 100% of covered services for the rest of the year.

Network Rules and How to Use Part C

Part C plans are managed care plans, which means they control costs by limiting which doctors and hospitals you can use. When you join a plan, you receive a list of in-network providers. You must use these doctors and hospitals for routine care. If you see an out-of-network provider, you pay more or the plan may not cover it at all, unless it is an emergency.

Most Part C plans require you to choose a primary care doctor (PCP) from the network. Your PCP coordinates your care and must refer you to specialists. If you see a specialist without a referral, the plan may not cover it. Some plans, called Preferred Provider Organization (PPO) plans, let you see out-of-network doctors without a referral, but you pay higher copays.

Before you join a plan, check whether your current doctors are in the network. You can search the plan's website or call the plan's customer service number. If your doctor is not in the network and you want to keep seeing them, you may need to choose a different plan or stay with Original Medicare.

When to Choose Part C and When to Avoid It

Part C works well if you are willing to use a network of doctors, prefer lower monthly premiums, want prescription drug coverage and extra benefits bundled together, and do not travel frequently outside your plan's service area. Part C plans are usually regional—they cover a specific county or group of counties—so if you spend winters in another state, you may not have coverage there.

Part C may not be right for you if you have a doctor or specialist you want to keep seeing and they are not in any available plan's network, if you travel frequently and want to see doctors anywhere in the country, if you have complex medical needs and want the freedom to see any specialist without a referral, or if you are enrolled in Medicaid (you cannot have both Medicaid and Part C at the same time).

If you have Original Medicare and are thinking about switching to Part C, ask your doctors whether they are in the plans you are considering. If you are already in Part C and want to switch back to Original Medicare, you can do so during open enrollment. You will also need to buy a separate Part D plan for prescriptions and may want to buy a Medigap policy to cover costs that Original Medicare does not pay.

How to Enroll in Part C

You can enroll in Part C during three main periods. The Initial Enrollment Period is the seven-month window that starts three months before the month you turn 65 and ends three months after. If you miss this window, you may pay a late enrollment penalty for as long as you have Medicare.

The Annual Enrollment Period runs from October 15 to December 7 each year. During this time, you can join a Part C plan, switch to a different Part C plan, or switch back to Original Medicare. Changes take effect January 1.

If you are new to Medicare or switching from Original Medicare, you can enroll through Medicare.gov, by phone at 1-800-MEDICARE, by mail using the enrollment form, or in person at a local Social Security office. If you are already in a Part C plan and want to switch plans, you can make the change online at Medicare.gov or by calling 1-800-MEDICARE.

Questions to Ask Your Doctor and Your Plan

Before you enroll in Part C, contact your current doctors and ask: "Are you in the [plan name] network?" and "Do I need a referral to see a specialist?" Ask the plan itself: "What is my out-of-pocket maximum?" "Does the plan cover [specific medication or service you use]?" and "What happens if I need care outside the service area?"

If you are already in Part C and something changes—you need a new medication, you want to see a new specialist, or you are moving—call your plan's customer service line and ask how the change affects your coverage. Do not assume your current coverage will continue.

Frequently Asked Questions

Can I have Part C and Medigap at the same time?

No. Medigap policies are designed to work with Original Medicare, not Part C. If you have Part C, you cannot buy Medigap. If you switch from Part C back to Original Medicare, you can then buy Medigap, though you may pay higher premiums if you wait to enroll.

What happens to my Part C coverage if I move to a different state?

Part C plans are regional and may not serve your new address. You will need to find a new plan in your new location or switch back to Original Medicare. Contact your current plan and Medicare to understand your options before you move.

Do I still pay the Part B premium if I have Part C?

Yes. You must continue paying your Part B premium (currently $164.90 per month for most people in 2024, though this changes yearly) even if you have Part C. The Part C plan premium is separate and is in addition to Part B.

Can I go back to Original Medicare after I choose Part C?

Yes, during the Annual Enrollment Period (October 15 to December 7). Your switch takes effect January 1. If you switch back to Original Medicare, you can enroll in Part D for prescriptions and may want to buy Medigap to cover costs Original Medicare does not pay.

What if my Part C plan stops serving my area?

Insurance companies sometimes exit markets. If your plan stops serving your county, Medicare will notify you and give you a special enrollment period to switch to a different Part C plan or return to Original Medicare without penalty, even outside the regular enrollment window.