What a Medicare Replacement Plan Is

A Medicare Replacement Plan (also called a Medicare Advantage plan or Part C) 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 to cover the same services. The plan itself becomes your insurer — you pay the plan's premium instead of Medicare's, and you use the plan's network of doctors and hospitals.

Medicare Replacement Plans must cover at least everything Original Medicare covers: hospital stays, doctor visits, and preventive care. Most plans also include prescription drug coverage (Part D) bundled in, and many add benefits Original Medicare does not, such as dental, vision, or hearing services. However, you cannot have both Original Medicare and a Medicare Replacement Plan at the same time — you choose one or the other.

Key Takeaways

  • A Medicare Replacement Plan is a private insurance option that replaces Original Medicare and is run by insurance companies under contract with Medicare.
  • These plans must cover hospital, doctor, and preventive services, and most include prescription drug coverage and extra benefits like dental or vision.
  • You pay a monthly premium to the plan (often lower than Original Medicare premiums), but you must use doctors and hospitals in the plan's network.
  • You can switch between Original Medicare and a Medicare Replacement Plan during the annual enrollment period (October 15 to December 7) or if you have a may have access to life event.
  • Out-of-pocket costs depend on the specific plan and how much care you use, so comparing plans side by side is important before you enroll.

How Medicare Replacement Plans Differ from Original Medicare

The biggest difference is who runs your coverage. With Original Medicare, the federal government pays your claims directly to providers. With a Medicare Replacement Plan, a private company (such as UnitedHealth, Humana, or Anthem) manages your benefits and decides which doctors and hospitals you can see. Original Medicare has no network — you can see any doctor who accepts Medicare anywhere in the country. A Medicare Replacement Plan requires you to use in-network providers, except in emergencies.

Cost structure also differs. Original Medicare has a monthly Part B premium (set by the federal government), a yearly deductible, and coinsurance (you pay a percentage of costs after the deductible). Medicare Replacement Plans often have lower or no monthly premiums, but they have copays (a fixed dollar amount per visit) and may have higher out-of-pocket maximums. Some plans charge nothing per month but have higher copays; others charge a premium but lower copays.

Original Medicare does not include prescription drugs, dental, vision, or hearing — you buy those separately if you want them. Most Medicare Replacement Plans bundle prescription drug coverage in and offer dental and vision as standard or optional add-ons. This can save money if you use these services, but it also means you are paying for coverage you may not need.

Types of Medicare Replacement Plans

The most common type is a Health Maintenance Organization (HMO) plan. HMO plans require you to choose a primary care doctor who coordinates your care and refers you to specialists. You must use in-network doctors except in emergencies. HMO premiums are often the lowest, but your choices are more limited.

A Preferred Provider Organization (PPO) plan gives you more flexibility. You can see any doctor without a referral, and you can go out of network — but it costs more. Out-of-network care is covered, but you pay a higher share of the cost. PPO premiums are usually higher than HMO premiums.

A Private Fee-for-Service (PFFS) plan lets you see any doctor who agrees to treat you under the plan's terms, without a network requirement. These are less common and may have higher costs. Some PFFS plans require you to enroll in a separate Part D plan for prescriptions.

A Special Needs Plan (SNP) is designed for people with specific conditions (such as diabetes or heart disease), people who live in a nursing home, or people who are also on Medicaid. These plans tailor benefits to your situation but have stricter enrollment rules.

Costs You Will Pay with a Medicare Replacement Plan

Monthly premiums vary widely. Some plans charge zero premium, while others charge $50 to $200 or more per month. The premium depends on the plan, your location, and the insurance company. Even if the premium is zero, you still pay the Part B premium to Medicare (unless you may have access to for a subsidy).

Copays are what you pay each time you use a service. A doctor visit might be $10 to $50; a specialist visit might be $40 to $75; a hospital stay might be $100 to $500 per admission. Prescription drugs have their own copay structure, often tiered by drug type. These amounts are set by the plan and vary from plan to plan.

An out-of-pocket maximum is the most you will pay in a year for in-network services. Once you reach it, the plan pays 100% of covered services for the rest of that year. Out-of-pocket maximums for 2024 cannot exceed $7,550 for in-network services in an HMO or PPO plan, though the actual maximum your plan sets may be lower. Out-of-network services have a separate, higher out-of-pocket maximum in PPO plans.

You do not pay the same amount every month. Some months you may have no doctor visits and pay only the premium. Other months with multiple visits or prescriptions, your costs add up quickly until you reach the out-of-pocket maximum.

When You Can Enroll or Switch Plans

The main enrollment window is the Annual Enrollment Period (AEP), which runs from October 15 to December 7 each year. During this time, you can enroll in a Medicare Replacement Plan for the first time, switch from Original Medicare to a plan, or switch from one plan to another. Coverage begins January 1 of the following year.

If you are new to Medicare (turning 65 or becoming may be able to access due to disability), you have a seven-month Initial Enrollment Period centered on your birthday month. You can enroll in a Medicare Replacement Plan during this window without waiting for October.

A may have access to life event — such as moving out of your plan's service area, losing other insurance, or a major change in income — may let you enroll or switch plans outside the normal windows. You must report the event to Medicare within 60 days to be may be able to access.

What to Ask Your Doctor Before You Enroll

Before you choose a Medicare Replacement Plan, talk to your current doctors and specialists. Ask whether they are in the plan's network and whether they are accepting new patients. If your main doctor is not in the network, switching plans may mean finding a new doctor, which can be disruptive if you have a long-standing relationship or a complex medical history.

Ask your doctor about any medications you take regularly. Find out whether they are on the plan's formulary (the list of covered drugs) and what tier they are on, because that determines your copay. Some plans do not cover certain drugs, or they require prior authorization (the plan's approval before you fill the prescription).

If you have a chronic condition that requires ongoing specialist care, ask whether the plan covers the specialists you see and how many visits per year are covered. Some plans limit specialist visits or require a referral from your primary care doctor.

When to Seek Help Comparing Plans

Comparing Medicare Replacement Plans can feel overwhelming because each plan has different premiums, copays, deductibles, and networks. The official Medicare website (Medicare.gov) has a plan comparison tool where you can enter your zip code, current doctors, and medications to see which plans cover them and what your estimated costs would be.

You can also call 1-800-MEDICARE to speak with a counselor who can walk you through your options. Many states have a State Health Insurance information Program (SHIP) that offers free, one-on-one counseling about Medicare plans. To find your state's SHIP, visit shiptalk.org or call 1-877-839-2675.

If you realize after enrolling that a plan is not working for you, you have a 14-day window to cancel and return to Original Medicare or switch to a different plan. After that, you are locked in until the next Annual Enrollment Period in October, unless you have a may have access to life event.

Frequently Asked Questions

Can I go back to Original Medicare after I enroll in a Medicare Replacement Plan?

Yes, but only during the Annual Enrollment Period (October 15 to December 7) or if you have a may have access to life event. You have a 14-day window after first enrolling in a plan to cancel and return to Original Medicare without penalty. After that, you are locked in until October unless circumstances change.

Do I still pay Medicare premiums if I have a Medicare Replacement Plan?

You still pay the Part B premium to Medicare (the amount deducted from your Social Security check or paid directly). You also pay the plan's monthly premium, if it has one. Some plans have zero premium, but you always pay Part B. If you have Part D prescription coverage through Original Medicare, you do not need it with a Medicare Replacement Plan because most plans include it.

What happens if I travel or move to a different state?

Medicare Replacement Plans have geographic service areas. If you move out of your plan's service area, you can switch to a different plan or return to Original Medicare. If you travel temporarily, emergency care is covered anywhere in the United States. For non-emergency care while traveling, check whether your plan covers out-of-network providers or has reciprocal agreements with plans in other states.

Are prescription drugs more expensive with a Medicare Replacement Plan?

It depends on the plan and the drugs you take. Some plans have very low copays for common medications, while others have higher copays or require you to try a cheaper drug first (step therapy). Compare the formulary and copay structure of plans you are considering against what you currently pay for prescriptions.

What if my doctor leaves the plan's network?

If your doctor stops accepting the plan, the plan must notify you and usually give you time to find a new doctor or switch plans. You may be able to request a continuity-of-care exception that lets you keep seeing that doctor for a limited time while you transition. Contact your plan when ready if this happens.