Once you have Medicare Part A and Part B (Original Medicare), you face one of the biggest decisions in your healthcare journey: should you add a Medicare Supplement plan, or switch to Medicare Advantage? Both paths give you valid, comprehensive coverage, but they work very differently, and the right choice depends on your health needs, budget, and personal priorities.

This guide breaks down the key differences so you can make an informed decision. If you’d like personalized help comparing your specific options, schedule a free consultation with Craig Smith.

The Core Difference

Medicare Advantage (Part C) is an alternative to Original Medicare. When you enroll in a Medicare Advantage plan, you receive your Medicare benefits through a private insurance company instead of directly through the government. Your provider bills the plan, not Medicare.

Medicare Supplement (Medigap) plans, on the other hand, work alongside Original Medicare. You keep your Original Medicare coverage, and the Medigap plan pays secondary, covering the deductibles, copays, and coinsurance that Original Medicare leaves behind.

Side-by-Side Comparison

How Medicare Advantage Works

With Medicare Advantage, a private insurance company administers your Medicare benefits. Instead of billing Medicare directly, your doctors bill the plan. Most plans use either an HMO or PPO network structure.

HMO Plans

HMO plans generally require you to choose a primary care doctor and get referrals before seeing specialists. Because the network is more restrictive, HMO plans often have the lowest premiums, frequently $0 per month.

PPO Plans

PPO plans allow you to see out-of-network providers, though at a higher cost. This added flexibility typically comes with a higher premium than comparable HMO plans.

The biggest advantage of Medicare Advantage is the inclusion of extra benefits, such as dental, vision, hearing aids, and sometimes even gym memberships or transportation to medical appointments, none of which Original Medicare or Medigap plans cover. Additionally, Medicare Advantage plans include a federally mandated annual out-of-pocket maximum, which limits your total exposure for covered services.

How Medicare Supplement Works

With a Medicare Supplement (Medigap) plan, you remain enrolled in Original Medicare. Medicare pays its share of your medical bills first, and then your Medigap plan pays its share according to the plan you’ve chosen.

Because Medigap plans are standardized by the federal government, a Plan G from one carrier provides identical coverage to a Plan G from any other carrier; only the premium differs. For a complete breakdown of what each lettered plan covers, see our Medicare Supplement Plans Comparison Chart.

The biggest advantage of Medigap is freedom and predictability. You can see any doctor in the country who accepts Medicare, no networks, no referrals. With Plan G, the most popular option for new enrollees, your only out-of-pocket cost for Medicare-covered services is the annual Part B deductible ($283 in 2026).

The tradeoff is a higher monthly premium and the need for a separate Part D plan since Medigap doesn’t include drug coverage.

Which Should You Choose?

Choose Medicare Advantage If:

• You want to minimize your monthly premium
• You’re comfortable using a network of doctors and getting referrals when needed
• You want extra benefits like dental, vision, and hearing built into your plan
• You don’t travel frequently or need care outside your local area
• You’re generally healthy and don’t anticipate frequent specialist visits

Choose Medicare Supplement If:

• You want the freedom to see any doctor who accepts Medicare, anywhere in the country
• You travel frequently or split time between multiple states
• You prefer highly predictable healthcare costs with minimal surprise bills
• You have ongoing health conditions that require frequent specialist care
• You don’t mind paying a higher monthly premium in exchange for lower out-of-pocket costs

Can You Switch Later?

Yes, but the rules differ depending on which direction you’re switching. Moving from Medicare Advantage to Medigap can be more difficult outside of your initial enrollment window, since most states allow Medigap insurers to use medical underwriting once your guaranteed issue rights expire. New York is a notable exception, offering year-round guaranteed issue rights for Medigap regardless of when you initially enrolled.

Switching from Medigap to Medicare Advantage is generally easier and can be done during the Annual Election Period (October 15 – December 7) each year.

For a complete overview of all Medicare enrollment windows, see our Medicare Enrollment Periods Explained guide.

Get a Free, Unbiased Comparison

There is no universally “better” option; the right choice depends entirely on your health needs, budget, travel habits, and personal preferences. As an independent Medicare broker, I represent multiple carriers across both Medicare Advantage and Medicare Supplement, so I can show you real options for both paths and help you compare them honestly. To understand how this works at no cost to you, see how Medicare brokers get paid.

For a full breakdown of 2026 costs across both plan types, see our Medicare Costs 2026 guide.

📅 Schedule Your Free Medicare Consultation

Craig Smith Insurance Group
📍 260 Madison Avenue, 8th Floor, New York, NY 10016
📍 1 Welwyn Road, Great Neck, NY 11022
📞 917-740-1895
✉️ craigsmith@csmedicare.net

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We are not connected with or endorsed by the United States Government or the federal Medicare program. We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.