Medicare Part C, commonly called Medicare Advantage, is an alternative way to receive your Medicare benefits. Instead of getting coverage directly from the federal government (Original Medicare), you enroll in a plan run by a private insurance company that contracts with Medicare. These plans must cover everything Original Medicare covers, but most also bundle in extras like dental, vision, and hearing coverage that Original Medicare does not provide.
How Part C Replaces Original Medicare
When you enroll in a Medicare Advantage plan, you’re not adding coverage on top of Original Medicare. You’re replacing it. The private insurer takes over responsibility for delivering all your Part A (hospital) and Part B (medical) benefits. You still pay your monthly Part B premium to Medicare, and some plans charge an additional monthly premium on top of that, though many charge $0 extra.
The key requirement is that every Medicare Advantage plan must cover all medically necessary services that Original Medicare covers. Plans also absorb new benefits that come from changes in law or Medicare policy, so you don’t lose ground when rules change. Where Part C differs most from Original Medicare is in how you access care: you’ll typically use a network of doctors and hospitals, and the cost-sharing structure (copays, coinsurance, deductibles) varies by plan rather than following Medicare’s standard rates.
Extra Benefits Beyond Parts A and B
The biggest draw for many people is the supplemental coverage. Most Medicare Advantage plans include benefits Original Medicare doesn’t offer: routine dental exams and cleanings, eye exams and eyeglasses, hearing tests and hearing aids. Many plans also cover fitness memberships, over-the-counter health products, and transportation to medical appointments. The specifics vary widely by plan and region, so two Medicare Advantage plans in the same zip code can offer very different extras.
The Out-of-Pocket Spending Cap
Original Medicare has no annual limit on what you can spend out of pocket, which is one reason many people on Original Medicare buy a supplemental Medigap policy. Medicare Advantage plans, by contrast, are required to cap your yearly out-of-pocket costs for Part A and Part B services. In 2025, that cap cannot exceed $9,350 for in-network services and $14,000 for in-network and out-of-network services combined. Many plans set their limits lower than these maximums. Once you hit the cap, you pay nothing for covered services for the rest of the year.
Prescription Drug Coverage
Many Medicare Advantage plans include Part D prescription drug coverage built in. These are called MAPD plans (Medicare Advantage Prescription Drug plans). If your plan includes drug coverage, you cannot also enroll in a separate standalone Part D plan. If your Medicare Advantage plan does not include drug coverage, you can join a standalone Part D plan alongside it, though these plan combinations are less common. When comparing plans, check whether the drugs you take are on the plan’s formulary and what your copays will be at each pharmacy tier.
Plan Types and How Networks Work
Medicare Advantage plans come in several structures, and the type you choose determines how much flexibility you have in picking doctors.
- HMO (Health Maintenance Organization): You generally must use doctors and hospitals in the plan’s network, except for emergencies or urgent care. You’ll need a referral from your primary care doctor to see a specialist. Some HMO plans offer a “point-of-service” option that allows limited out-of-network care at higher cost.
- PPO (Preferred Provider Organization): You can see any provider in or out of network without a referral. Out-of-network care costs more, but you have the option. This is the most flexible common plan type.
- PFFS (Private Fee-for-Service): You can go to any Medicare-approved provider that accepts the plan’s payment terms. No referrals required. However, providers are not obligated to accept the plan, so you need to confirm before each visit.
Your choice of plan type matters most if you have established relationships with specific doctors or if you travel frequently. PPO and PFFS plans give you more freedom, while HMOs typically offer lower premiums and copays in exchange for a tighter network.
Special Needs Plans
A subset of Medicare Advantage plans called Special Needs Plans (SNPs) are designed for people with specific circumstances. There are three types. Dual Eligible SNPs (D-SNPs) serve people who qualify for both Medicare and Medicaid, helping coordinate benefits between the two programs. Chronic Condition SNPs (C-SNPs) are built around managing a specific severe or chronic illness, and they can limit membership to people with that condition. Institutional SNPs (I-SNPs) serve people who live in nursing facilities or require an institutional level of care.
To join any SNP, you need both Part A and Part B, must live in the plan’s service area, and must meet the eligibility criteria for that specific plan type. You can only stay enrolled as long as you continue to meet the qualifying conditions.
Who Can Enroll and When
To join a Medicare Advantage plan, you need to have both Medicare Part A and Part B and live in the plan’s service area. Your first opportunity comes during your Initial Enrollment Period: a seven-month window that starts three months before you turn 65, includes your birthday month, and extends three months after. If you qualify for Medicare through disability before age 65, your enrollment window begins 21 months after you start receiving disability benefits and runs through the 28th month.
After that initial window, you have two regular opportunities each year:
- Annual Enrollment Period (October 15 to December 7): You can join, switch, or drop a Medicare Advantage plan. You can also move between Original Medicare and Medicare Advantage. Changes take effect January 1.
- Medicare Advantage Open Enrollment Period (January 1 to March 31): If you’re already in a Medicare Advantage plan, you can switch to a different one or drop back to Original Medicare and join a standalone drug plan. You can make one change during this window, and it takes effect the first of the following month.
Tradeoffs to Consider
Medicare Advantage plans can save money through lower premiums, bundled extras, and the annual spending cap. But they come with tradeoffs. Network restrictions mean your preferred doctor or hospital may not be covered, or may cost significantly more. Plans can also require prior authorization before approving certain services, which can delay care. If you move or spend extended time outside your plan’s service area, you may have limited or no non-emergency coverage depending on the plan type.
Original Medicare, by comparison, lets you see any provider nationwide that accepts Medicare, with no referrals or prior authorization. But it has no spending cap and doesn’t cover dental, vision, or hearing, so many people on Original Medicare purchase a Medigap policy and a standalone Part D plan to fill those gaps, which adds to monthly costs. The right choice depends on your health, your budget, your doctors, and how much flexibility you need.