What Medicare Advantage Is and Who Sells It

Medicare Advantage is a way to receive your Medicare benefits through a private insurance company instead of through Original Medicare (the federal program). The federal government pays the private insurer a fixed amount each month to cover your care. The private company then becomes responsible for providing Part A (hospital) and Part B (medical) coverage, and most also include prescription drug coverage as Part D.

Private insurers that offer Medicare Advantage include national carriers like UnitedHealthcare, Humana, Anthem, and Aetna, as well as regional plans that operate in specific states or counties. You cannot buy a Medicare Advantage plan directly from Medicare — you must enroll through the private insurance company that offers the plan in your area.

Medicare Advantage plans are also called Part C plans. They are not supplemental insurance (Medigap); they replace Original Medicare entirely once you enroll. This distinction matters because your coverage rules, costs, and provider networks change when you switch.

Key Takeaways

  • Medicare Advantage plans are sold by private insurance companies and replace Original Medicare, not supplement it.
  • Most plans include prescription drug coverage, hospital care, and doctor visits, but you pay different amounts depending on which plan and which provider you use.
  • Plans vary by county and state, so the options available to you depend on where you live.
  • You enroll during the Annual Enrollment Period (October 15 to December 7 each year) or when you first become may be able to access for Medicare.
  • Switching back to Original Medicare is possible but only during specific enrollment windows, so choosing a plan is not a permanent lock-in.

How Private Insurers Structure Medicare Advantage Plans

Each private insurance company designs its own Medicare Advantage plan with different cost structures and rules. Most plans use a network model: you pay less when you see doctors and hospitals that are in the plan's network, and you pay more (or nothing is covered) when you go out of network. Some plans are Health Maintenance Organizations (HMOs), which require you to pick a primary care doctor and get referrals for specialists. Others are Preferred Provider Organizations (PPOs), which give you more freedom to see specialists without a referral but still charge more for out-of-network care.

The costs you see on paper — the monthly premium, the deductible, the copay for a doctor visit — are set by the private company, not by Medicare. Two plans from different insurers in the same county can have very different costs and coverage rules. One plan might charge $0 monthly premium but $45 per doctor visit, while another charges $50 monthly but $15 per visit.

Most Medicare Advantage plans include dental, vision, and hearing coverage, which Original Medicare does not. However, the scope of that coverage (how many cleanings per year, whether it covers dentures, what hearing aids cost) varies widely by plan and insurer.

What You Pay and When

Medicare Advantage plans have four main costs: the monthly premium, the annual deductible, copays for specific services, and coinsurance (a percentage of the cost you pay after the deductible). You also pay the Part B premium to Medicare itself — that does not change based on which plan you choose.

Many plans advertise $0 monthly premium, which means you pay nothing extra beyond your Part B premium. However, a $0 premium plan often has higher copays or a higher deductible than a plan with a monthly premium. There is no rule that says a $0 premium plan is cheaper overall; it depends on how much care you actually use.

Plans have an out-of-pocket maximum — a yearly cap on what you pay for in-network care. Once you reach that limit, the plan pays 100% of your in-network costs for the rest of the year. Out-of-pocket maximums vary by plan but are set by Medicare regulation, so no plan can charge you unlimited amounts.

How to Find and Compare Plans in Your Area

The plans available to you depend entirely on where you live. A plan offered by Humana in Florida may not exist in Ohio. To see which Medicare Advantage plans are sold in your county, you can visit Medicare.gov and use the plan finder tool, or call 1-800-MEDICARE to speak with someone who can list your options.

When you search, you will see the plan name, the insurer, the monthly premium, the deductible, copays for common services (doctor visit, specialist, hospital stay, prescription drugs), and whether the plan includes dental and vision. You can also see which hospitals and doctors are in each plan's network, though that information is sometimes easier to find on the insurer's website than on Medicare.gov.

Comparing plans side by side is important because the cheapest premium is not always the cheapest plan overall. A tool called the "Plan Finder" on Medicare.gov lets you enter your current doctors and medications and shows you which plans cover them and what your costs would be under each plan. This is more useful than comparing premiums alone.

Enrollment Windows and When You Can Switch

You can enroll in a Medicare Advantage plan during the Annual Enrollment Period, which runs from October 15 to December 7 each year. Coverage begins January 1 of the following year. If you are newly may be able to access for Medicare (turning 65 or becoming may be able to access due to disability), you have a seven-month Initial Enrollment Period centered on your may be able to access month.

If you are already enrolled in a Medicare Advantage plan and want to switch to a different plan or back to Original Medicare, you can do so during the Annual Enrollment Period. You cannot switch plans outside this window unless you have a may have access to life event — moving to a new county, losing employer coverage, or becoming may be able to access for Medicaid, for example.

Some people enroll in a Medicare Advantage plan, use it for a year, and then decide they prefer Original Medicare. This is allowed, but you can only make the switch during the Annual Enrollment Period or during the Medicare Advantage Open Enrollment Period (January 1 to March 31), which allows you to switch to a different Medicare Advantage plan or to Original Medicare.

Network Restrictions and Out-of-Network Costs

The biggest operational difference between Medicare Advantage and Original Medicare is the network. With Original Medicare, you can see any doctor or hospital that accepts Medicare, anywhere in the country. With most Medicare Advantage plans, you must use in-network providers or pay significantly more.

If you see an out-of-network doctor, you typically pay a higher copay or coinsurance, or the visit may not be covered at all. Some plans cover out-of-network emergency care, but routine care out of network is usually your responsibility. This matters if you travel frequently, live part of the year in another state, or have a specialist you want to keep seeing who is not in the plan's network.

Before enrolling in a plan, check whether your current doctors and your preferred hospital are in the network. If your doctor is not listed, contact the doctor's office directly to confirm — network lists are sometimes outdated. If your doctor is out of network and you want to keep seeing them, you may need to choose a different plan or stick with Original Medicare.

Prescription Drug Coverage Under Medicare Advantage

Most Medicare Advantage plans include prescription drug coverage (Part D) as part of the plan. You do not buy a separate Part D plan; the coverage is built in. However, the drugs covered, the copays for each drug, and the pharmacy network vary by plan.

Each plan has a formulary — a list of covered drugs organized by tier. Tier 1 drugs (usually generics) have the lowest copay. Tier 2 and 3 drugs (brand-name and specialty drugs) have higher copays. Some drugs may not be on the formulary at all, meaning the plan does not cover them, or you may need prior authorization from the plan before the pharmacy will fill the prescription.

If you take expensive or specialty medications, check the plan's formulary before enrolling. A plan with a low monthly premium might have high copays for the drugs you take, making it more expensive overall. The plan finder tool on Medicare.gov lets you enter your medications and see what you would pay under each plan.

Frequently Asked Questions

Can I use my Medicare Advantage plan if I travel or move to another state?

Most Medicare Advantage plans only cover care within their service area, which is usually your home county or state. If you travel, you may have emergency coverage but not routine care. If you move permanently to another state, you can switch to a different Medicare Advantage plan or to Original Medicare during the Annual Enrollment Period or within 60 days of moving.

What happens to my Medicare Advantage plan if the insurance company stops offering it?

If your plan is discontinued, Medicare sends you a notice and you can switch to a different plan without waiting for the Annual Enrollment Period. You have until the end of the month following the notice to make a change, and your new coverage begins the first of the next month.

Do I still pay the Part B premium if I have a Medicare Advantage plan?

Yes. You pay your Part B premium to Medicare every month, regardless of which plan you choose. The Medicare Advantage plan premium (if any) is separate and goes to the private insurance company. Some plans have $0 additional premium, but you always pay Part B.

Can I have both Medicare Advantage and Medigap at the same time?

No. Medicare does not allow you to enroll in both. If you have Medicare Advantage, you cannot buy a Medigap policy. If you switch from Medicare Advantage back to Original Medicare, you can then buy Medigap, but you may face higher premiums or underwriting depending on your state and how long you were without it.

What if my doctor leaves the plan's network?

If your in-network doctor leaves the plan, the plan usually gives you a grace period to find a new doctor or to switch to a different plan. Contact your plan when ready if this happens. You may be able to switch plans outside the Annual Enrollment Period if losing your doctor is considered a network change.