What Are the Different Types of Medicare Plans?
Table of Contents
Medicare Parts A, B, C, and D: The Building Blocks of Coverage
Part A: Hospital Coverage
Part B: Outpatient and Medical Coverage
Part D: Prescription Drug Coverage
Original Medicare vs. Medicare Advantage: Two Paths to Coverage
How Original Medicare Works
How Medicare Advantage (Part C) Works
Medicare Advantage Plan Types: HMO, PPO, PFFS, and SNP
Health Maintenance Organization (HMO) Plans
Preferred Provider Organization (PPO) Plans
Private Fee-for-Service (PFFS) and Special Needs Plans (SNP)
Medigap Plans: Filling the Gaps in Original Medicare
How Plan Choice Affects Travel and Out-of-Area Care
Eligibility and Enrollment Timing: When to Sign Up
The enrollment periods that actually matter
Working past 65: the exception that trips people up
Switching later: what you can and can't do
A practical way to think about timing
Side-by-Side Comparison: Original Medicare, Medicare Advantage, and Medigap
What the table doesn't tell you
The cost tradeoff, in plain terms
A quick decision path
Where Medigap fits, and where it doesn't
Coverage Limitations and Common Exclusions
Frequently Asked Questions
Last Updated: October 8, 2026
Medicare Parts A, B, C, and D: The Building Blocks of Coverage
Medicare is the federal health insurance program for people 65 and older, some younger people with disabilities, and people with end-stage renal disease.
Here is how the four parts break down:
Part A: Hospital insurance
Part B: Medical insurance
Part C: Medicare Advantage, an alternative way to get Part A and B
Parts A and B together are Original Medicare; Part C is a private-plan option; Part D can stand alone or be built into a Part C plan.
Part A: Hospital Coverage
Part A covers inpatient hospital stays, skilled nursing facility care after a hospital stay, hospice care, and some home health care. Most people get it premium-free because they or a spouse paid Medicare taxes while working. Its deductible applies per benefit period, not per year, so a long hospital stay can trigger a second deductible in the same calendar year.
Part B: Outpatient and Medical Coverage
Part B covers doctor visits, outpatient care, preventive services, lab tests, and durable medical equipment. Everyone pays a Part B premium based on income, but many preventive screenings cost nothing extra.
Part D: Prescription Drug Coverage
Part D is prescription drug coverage from private insurers. It's optional, but skipping it when first eligible can trigger a lifelong late enrollment penalty. Each plan has its own formulary, so compare by your actual prescriptions, not premium alone.
Watch Out If you go 63 days or more without creditable drug coverage after you're first eligible, you'll pay a late enrollment penalty added to your Part D premium for as long as you have Part D (Avoid late enrollment penalties). The penalty is permanent.
Original Medicare vs. Medicare Advantage: Two Paths to Coverage
Original Medicare is run by the federal government and lets you see any provider nationwide who accepts Medicare. Medicare Advantage is run by private insurers and usually limits you to a network. The choice is flexibility versus extras: Original Medicare gives the widest provider access, while Medicare Advantage often bundles dental, vision, and hearing in exchange for some freedom.
How Original Medicare Works
With Original Medicare, you can see any doctor or hospital in the country that accepts Medicare, with no referrals or network restrictions. The trade-off: no out-of-pocket maximum, which is why many people pair it with a Medigap policy.
How Medicare Advantage (Part C) Works
Medicare Advantage, or Part C, is an all-in-one alternative: private insurers contract with Medicare to provide Part A and Part B benefits, and most plans include Part D. Plans must cover everything Original Medicare covers but set their own networks, referrals, and prior authorizations, so costs vary widely by plan and county.
Key Takeaway The single most important thing to check before choosing Medicare Advantage is whether your doctors and hospitals are in the plan's network. A plan that saves you money on paper costs you more if your specialist is out-of-network.
Medicare Advantage Plan Types: HMO, PPO, PFFS, and SNP
Medicare Advantage comes in four main structures, HMO, PPO, PFFS, and SNP, each handling networks and referrals differently.
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Health Maintenance Organization (HMO) Plans
HMO plans usually require in-network providers and a primary care provider, plus referrals for specialists. They tend to have lower premiums and out-of-pocket costs, but care outside the network generally isn't covered except in emergencies.
Preferred Provider Organization (PPO) Plans
PPO plans let you see in-network providers at lower cost and out-of-network providers at higher cost, with no specialist referrals. Premiums are higher, but if you travel often or want to keep an out-of-network doctor, a PPO is usually the better fit.
Private Fee-for-Service (PFFS) and Special Needs Plans (SNP)
PFFS plans let you see any provider who agrees to the plan's terms and payment rates at the time of service, not every provider does, so check before each visit. Special Needs Plans (SNPs) serve specific groups: people with certain chronic conditions, people who qualify for both Medicare and Medicaid, or people in institutions, tailoring benefits and networks to those groups.
Plan Type | Referrals Needed | Network Rules | Best For |
HMO | Usually yes | In-network only | Lower costs, local care |
PPO | No | In and out of network | Flexibility, travel |
PFFS | No | Provider must agree to terms | Rural areas, fewer networks |
SNP | Varies | Tailored to condition | Chronic conditions, dual-eligible |
Medigap Plans: Filling the Gaps in Original Medicare
Medigap, or Medicare Supplement Insurance, is private insurance that pays some of the costs Original Medicare leaves behind, deductibles, copayments, and coinsurance.
One rule matters more than any other: the best time to buy Medigap is during your six-month Medigap Open Enrollment Period, which starts when you're 65 and enrolled in Part B.
Pro Tip If you have health conditions and think you might want Medigap later, buy it during your open enrollment window. Waiting until you "need it" often means you can't get it, or you pay far more.
How Plan Choice Affects Travel and Out-of-Area Care
Travel is where plan choice really shows its teeth. Original Medicare works anywhere in the country that accepts Medicare, while Medicare Advantage HMOs usually don't cover routine care outside their service area.
Original Medicare: covered nationwide, no network limits
Medicare Advantage HMO: emergency care covered, routine care outside the area usually not
Medicare Advantage PPO: some out-of-area coverage, often at higher cost
If you spend months away from home, check the plan's travel rules before you enroll, not after.
Eligibility and Enrollment Timing: When to Sign Up
Most people become eligible for Medicare at 65. If you already receive Social Security or Railroad Retirement Board benefits, you're enrolled in Part A and Part B automatically; otherwise you enroll through Social Security online, by phone, or at a local office. You may also qualify earlier after 24 months of Social Security disability benefits, or with end-stage renal disease or ALS, confirm your start date before making plan decisions.
The enrollment periods that actually matter
There isn't one enrollment window, there are several, each doing something different.
Initial Enrollment Period (IEP): A seven-month window around your 65th birthday, the three months before, your birthday month, and the three months after. Sign up for Part A and/or Part B, and add Part D or Medicare Advantage.
General Enrollment Period (GEP): January 1 through March 31 for people who missed their IEP and don't qualify for a Special Enrollment Period. Coverage generally starts the month after you sign up, which can leave a gap.
Annual Enrollment Period (AEP): October 15 through December 7. Anyone with Medicare can switch between Original Medicare and Medicare Advantage, change Medicare Advantage plans, or join, drop, or change a Part D plan. Changes take effect January 1.
AEP is for switching. The MA OEP is for undoing a Medicare Advantage choice you regret. The IEP is for getting in the door. Confusing these three is the single most common source of coverage gaps we see.
Working past 65: the exception that trips people up
If you or your spouse still works and has employer coverage from a company with 20 or more employees, that coverage is generally primary to Medicare. You can often delay Part B without penalty, but you must sign up within eight months of losing that coverage, or you'll pay the late enrollment penalty for as long as you have Part B.
Miss your Initial Enrollment Period and you may pay a Part B late enrollment penalty of 10% for each 12-month period you could have had Part B but didn't. In most cases, that penalty lasts as long as you have Part B. The Part D penalty is calculated differently, roughly 1% of the national base beneficiary premium for each month you went without creditable drug coverage, and it also lasts as long as you have Part D.
Switching later: what you can and can't do
Once enrolled, your ability to change plans depends on where you are:
In Original Medicare: Add or drop Part D during AEP, and apply for Medigap anytime, but outside your Medigap Open Enrollment Period, insurers in most states can deny you or charge more based on health.
In Medicare Advantage: Switch plans during AEP, or use the MA OEP in January through March to make one change. Moving, losing coverage, or qualifying for Medicaid may open an SEP.
Leaving Medicare Advantage for Original Medicare plus Medigap: The hardest move later in life. In most states, Medigap insurers can underwrite you once your initial Medigap Open Enrollment Period has passed; a handful of states offer guaranteed-issue rights beyond federal rules.
A practical way to think about timing
The decision isn't just which plan, it's when:
Turning 65 and not working: Enroll in Part A and Part B during your IEP, and decide on Medigap, Medicare Advantage, or Original Medicare plus Part D before your Part B start date, since Medigap open enrollment runs concurrently with your first six months of Part B.
Turning 65 and still working with creditable coverage: You can usually delay Part B, but confirm your employer's size and whether your drug coverage is creditable, and sign up within eight months of losing coverage.
Already on Medicare and unhappy: Use AEP (October 15-December 7) to switch for January 1, or the MA OEP (January 1-March 31) if you're in Medicare Advantage.
Getting the timing right is often worth more than optimizing the plan itself, a wrong move can mean a permanent penalty, a coverage gap, or being locked out of Medigap.
Side-by-Side Comparison: Original Medicare, Medicare Advantage, and Medigap
The three paths differ in cost, freedom, and coverage:
Feature | Original Medicare | Medicare Advantage | Medigap |
Who runs it | Federal government | Private insurers | Private insurers |
Provider network | Any Medicare provider nationwide | Usually limited to a service area | Any Medicare provider nationwide |
Referrals | Not needed | Often required (HMO) | Not needed |
Drug coverage | Add Part D separately | Often included | Add Part D separately |
Monthly premium | Part B premium (plus Part A if applicable) | Part B premium plus plan premium (some plans $0) | Part B premium plus Medigap premium |
Out-of-pocket cap | None | Yes, an annual maximum | None on the plan itself, but Medigap caps what you pay for covered services |
Extra benefits | Limited | Dental, vision, hearing, fitness, OTC allowances | None |
Prior authorization | Rare | Common | Rare |
Travel coverage | Nationwide | Emergency care only outside service area (PPO may cover more) | Nationwide, follows Original Medicare |
Best for | Maximum flexibility | Lower premiums, extras, network-tolerant | Capping Original Medicare costs |
What the table doesn't tell you
The table shows structure. The decision comes down to three questions.
1. How much risk can you absorb in a bad year? Original Medicare alone has no out-of-pocket maximum.
2. How important is keeping your current doctors? Original Medicare and Medigap let you see any provider nationwide who accepts Medicare.
3. How much do you travel or split time between states? Original Medicare and Medigap travel with you.
The cost tradeoff, in plain terms
Original Medicare plus Medigap typically has the highest monthly premium but the most predictable costs, you pay more each month and less when you use care. Medicare Advantage typically has the lowest monthly premium (some plans $0 beyond the Part B premium), but costs show up at the point of care through copays, coinsurance, and prior authorization.
The honest take: there's no single best option. It depends on your doctors, your budget, your health, and how much you travel. Original Medicare plus Medigap costs more monthly but caps your risk. Medicare Advantage costs less monthly but limits your network. The right answer is the one that matches your actual life, not the one with the lowest advertised premium.
A quick decision path
Chronic conditions, multiple specialists, or frequent travel: Original Medicare plus Medigap plus Part D is usually the strongest fit.
Generally healthy, want lower premiums, don't mind a network: Medicare Advantage may save you money.
Healthy now but worried about future risk: Original Medicare plus Medigap locks in predictability, but buy Medigap during your open enrollment window, before health questions apply.
Where Medigap fits, and where it doesn't
Medigap only works with Original Medicare, you cannot use it with a Medicare Advantage plan or to supplement its cost-sharing. If you start in Medicare Advantage and later want Medigap, you'll generally have to pass medical underwriting unless you qualify for a guaranteed-issue right, which is why the timing of your initial choice matters so much.
Coverage Limitations and Common Exclusions
Medicare doesn't cover everything, and knowing the gaps ahead of time prevents unwelcome bills. What Medicare generally does not cover:
Long-term custodial care, like help with bathing and dressing
Most dental care, unless it's part of a covered procedure
Routine eye exams and most eyeglasses
Some Medicare Advantage plans add dental, vision, and hearing benefits; Original Medicare does not, which is one of the main reasons people choose Part C.
Choosing among the different types of Medicare plans comes down to trade-offs, not a single right answer. The wrong pick can mean surprise bills, lost doctors, or penalties that follow you for years.
Frequently Asked Questions
What is the difference between Original Medicare and Medicare Advantage?
Original Medicare (Parts A and B) is government-administered coverage that lets you see any provider who accepts Medicare nationwide. Medicare Advantage (Part C) is private insurance that bundles Part A, Part B, and usually Part D into one plan, often with extra benefits like dental or vision. Advantage plans typically use provider networks and may require referrals, while Original Medicare does not. Your choice affects costs, flexibility, and which doctors you can see.
What are the different types of Medicare Advantage plans?
The main Medicare Advantage plan types are Health Maintenance Organization (HMO), Preferred Provider Organization (PPO), Private Fee-for-Service (PFFS), and Special Needs Plans (SNP). HMOs usually require you to stay in-network and get referrals for specialists. PPOs let you see out-of-network providers at higher cost. PFFS plans set their own payment terms with providers. SNPs serve people with specific chronic conditions or dual eligibility. Each type has different rules for networks, referrals, and costs.
Can I drop my Medicare Advantage plan and go back to Original Medicare?
Yes, you can switch from Medicare Advantage back to Original Medicare during the Annual Enrollment Period (October 15 to December 7) or during a Medicare Advantage Open Enrollment Period (January 1 to March 31). However, if you want to add a Medigap policy after leaving Advantage, you may face medical underwriting in most states, which means you could be denied or charged more. Timing matters, so review your options before making a change.
What does Medicare not cover?
Original Medicare does not cover routine dental care, vision exams, hearing aids, long-term custodial care, or most care received outside the United States. It also does not cap your annual out-of-pocket spending unless you add a Medigap policy or enroll in Medicare Advantage. Some Medicare Advantage plans include extra benefits like dental or vision, but coverage varies by plan. Always check the plan's summary of benefits to confirm what is included.
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