Learning center · Choosing your coverage
Medicare Advantage vs Medigap in South Dakota
Two different ways to fill the gaps in Medicare. The right one depends on your doctors, your budget, how much you travel, and how you feel about surprises.
The short answer
Medicare Advantage (Part C) is a private plan that replaces how Original Medicare pays for your care: it usually has a provider network, often includes drug coverage, and caps your yearly out-of-pocket costs for covered services, at no more than $9,850 in network in 2027 under CMS rules. Medigap is a supplement you add to Original Medicare: you pay a monthly premium, and it pays some or most of the deductibles and 20% coinsurance Original Medicare leaves you, at any doctor or hospital in the U.S. that takes Medicare. You cannot have both at once. In South Dakota, the safest time to buy Medigap without health questions is your six-month open enrollment period after you turn 65 and enroll in Part B, so the first choice carries the most weight.
- Original Medicare has no yearly out-of-pocket limit; Medicare Advantage plans must have one ($9,250 in network for 2026, $9,850 for 2027 at most).
- Medigap lets you see any provider in the U.S. who takes Medicare. Medicare Advantage usually uses a network and may require referrals and prior approval.
- Medigap does not include drug coverage; you add a Part D plan. Most Medicare Advantage plans include Part D.
- South Dakota's Division of Insurance confirms a six-month Medigap open enrollment at 65 regardless of health.
- Leaving Medicare Advantage later may mean answering health questions to buy Medigap.
Two paths, defined
Original Medicare is Part A (hospital) and Part B (medical), run by the federal government. For Part B services you usually pay 20% of the Medicare-approved amount after the yearly deductible, which is $283 in 2026, according to CMS. There is no annual cap on that 20%.
Medigap, also called Medicare Supplement Insurance, is a private policy that sits on top of Original Medicare and pays some or all of those leftover costs. Medigap policies are standardized and identified by letters, so a Plan G from one insurer covers the same benefits as a Plan G from another; what differs is the premium and the company.
Medicare Advantage, or Part C, is a private plan approved by Medicare that takes the place of Original Medicare for paying claims. It must cover everything Original Medicare covers, can add extras such as some dental, vision and hearing benefits, and usually includes Part D drug coverage. You still pay your Part B premium. Our existing pages on Medicare Advantage plans and Medicare Supplement plans cover each on its own.
Side by side
| Original Medicare + Medigap (+ Part D) | Medicare Advantage | |
|---|---|---|
| Doctors and hospitals | Any provider in the U.S. that takes Medicare | Usually the plan's network and service area for non-emergency care; some plans cover out of network at higher cost |
| Referrals and prior approval | In most cases no specialist referral and no prior authorization | May need referrals for specialists and prior authorization for some services |
| Yearly out-of-pocket limit | None in Original Medicare; Medigap fills most or all of the gap depending on the letter | Required; in-network ceiling $9,250 (2026) and $9,850 (2027) |
| Premiums | Part B premium + Medigap premium + Part D premium | Part B premium + plan premium, which can be $0 in some plans |
| Drug coverage | Separate Part D plan | Included in most plans |
| Extra benefits | Not included | Some plans add dental, vision or hearing benefits |
| Care outside the U.S. | Some Medigap letters cover foreign travel emergencies, up to plan limits | Generally not covered; some plans add it as an extra |
Source: Medicare.gov, Compare Original Medicare & Medicare Advantage (checked October 19, 2026); CMS Final CY2026 and CY2027 Part C bid review standards for the out-of-pocket ceilings.
The ceilings above are the most a plan may set. Many plans set lower limits. A PPO plan, which pays for some care out of network, also has a combined in- and out-of-network ceiling: $13,900 for 2026 and $14,800 for 2027, under the CMS 2027 bid review standards.
The Medigap letters that matter most
Medicare.gov's Medigap comparison chart lists the standard letters: A, B, C, D, F, G, K, L, M and N. Plans C and F are only available to people who became eligible for Medicare before January 1, 2020. For most people new to Medicare today, the conversation is about G and N, with K, L and the high-deductible G as lower-premium options.
| Plan | What you pay | Period |
|---|---|---|
| Plan G | The Part B deductible ($283 in 2026); then Plan G pays the Part B coinsurance and the other gaps it covers | 2026 |
| Plan N | The Part B deductible, plus copays of up to $20 for some office visits and up to $50 for emergency room visits that don't lead to admission | 2026 |
| Plan K | A share of costs until a yearly out-of-pocket limit of $8,000 | 2026 |
| Plan L | A share of costs until a yearly out-of-pocket limit of $4,000 | 2026 |
| High-deductible Plan G | Up to $2,950 before the policy pays (2026); $3,050 for 2027 | 2026 and 2027 |
Source: Medicare.gov, Compare Medigap plan benefits (2026 figures); CMS, F, G & J deductible announcement for calendar year 2027.
The South Dakota Division of Insurance also notes, on its Medicare supplement page, that some companies in the state offer Medicare Select, a version of Medigap that requires network hospitals except in an emergency, and that a Medigap policy is required to cover changes in Medicare's deductibles, so you do not need to change policies when deductibles change.
South Dakota buying windows
This is where the decision gets lopsided. Federally, your Medigap Open Enrollment Period is 6 months, starting the first month you are 65 or older and enrolled in Part B, according to Medicare.gov. Medicare.gov calls it the best time to buy; after it, your options may be limited and the policy may cost more.
The South Dakota Division of Insurance states the same six-month window for people 65 and older, during which a Medicare supplement policy can be obtained regardless of your health condition. It adds that people under 65 who qualify for Medicare because of a disability have a six-month open enrollment period beginning on the date they enroll in Part B.
After that window, you can still apply for Medigap at any time, but an insurer can ask health questions and decline you or charge more, except in specific federal guaranteed-issue situations. Two of those matter most here: Medicare.gov describes a trial right to drop a Medicare Advantage plan within 12 months of first joining and return to Original Medicare, and a 63-day window to buy certain policies after some types of coverage end. For the full South Dakota picture, see our existing South Dakota Medigap guide and our answer on switching from Medicare Advantage to Medigap.
The practical upshot: choosing Medicare Advantage at 65 and switching to Medigap at 72 can be harder than the reverse. If Medigap is ever going to be your choice, the open enrollment window is the cleanest time to make it.
How to choose
- Start with your doctors. If you want to keep seeing a particular clinic or specialist, check whether each Medicare Advantage plan you are considering has them in network. With Medigap, any provider who takes Medicare will do.
- List your prescriptions. With Medigap you will add a Part D plan; with Medicare Advantage the drug coverage is usually built in. Either way, check each drug on the plan's list.
- Think about the bad year, not the average year. Add up premiums plus the most you could pay out of pocket. Medigap tends to cost more every month and less in a heavy-use year; Medicare Advantage tends to be the reverse.
- Think about travel. Snowbirds who spend winters in Arizona or Texas should look hard at how a plan's network works away from home.
- Decide inside your window. If you are leaning toward Medigap, use the six-month open enrollment.
Our guide to checking doctors and drugs before you choose walks through steps 1 and 2 with Medicare.gov's tools.
Weighing the two for yourself or a parent?
We compare the Medicare Advantage and Medigap plans we offer side by side against your doctors, your prescriptions and a realistic bad year, so you can decide on facts.
Book a conversation →Questions, answered
What is the main difference between Medicare Advantage and Medigap?
Medicare Advantage replaces how Original Medicare pays for your care, usually with a network and a yearly out-of-pocket limit. Medigap is added on top of Original Medicare and pays some or all of the costs Original Medicare leaves you, at any provider in the U.S. that takes Medicare.
Can I have Medicare Advantage and Medigap at the same time?
No. Medicare.gov says you cannot buy Medigap to cover your out-of-pocket costs if you are in a Medicare Advantage plan.
What is the Medicare Advantage out-of-pocket limit for 2027?
Under CMS's final 2027 standards, a plan's in-network out-of-pocket limit can be no higher than $9,850, and a PPO's combined limit no higher than $14,800. Many plans set lower limits.
When can I buy Medigap in South Dakota without health questions?
During your six-month Medigap open enrollment period, which starts when you are 65 or older and enrolled in Part B. The South Dakota Division of Insurance says a policy can be obtained regardless of health during that period.
Does Medigap include prescription drug coverage?
No. Medigap policies sold today do not include drug coverage, so people with Original Medicare and Medigap usually add a separate Part D plan.
Can I switch from Medicare Advantage to Medigap later?
You can apply, but outside your open enrollment period and specific guaranteed-issue situations, an insurer can ask health questions. If you joined Medicare Advantage when first eligible, Medicare.gov describes a trial right to return to Original Medicare within 12 months.
What is Medicare Select?
A version of Medigap that requires you to use network hospitals except in an emergency. The South Dakota Division of Insurance says some companies offer it in the state.
What does Medigap Plan N cost me at the doctor?
Medicare.gov says that with Plan N you pay the Part B deductible plus a copay of up to $20 for some office visits and up to $50 for emergency room visits that don't result in an inpatient admission.
Figures and sources
Every figure on this page, where it comes from, and the period it covers. Checked October 19, 2026.
| Figure | Source | Period |
|---|---|---|
| Original Medicare: no yearly out-of-pocket limit; Medicare Advantage: yearly limit; can't buy Medigap with Medicare Advantage; network, referral and prior-authorization differences | Medicare.gov, Compare Original Medicare & Medicare Advantage | Current, checked October 19, 2026 |
| Medicare Advantage in-network out-of-pocket ceiling $9,250; PPO combined ceiling $13,900 | CMS, Final CY2026 Part C Bid Review Standards | 2026 plan year |
| Medicare Advantage in-network out-of-pocket ceiling $9,850; PPO combined ceiling $14,800 | CMS, Final CY2027 Part C Bid Review Standards (April 22, 2026) | 2027 plan year |
| Medigap letters A, B, C, D, F, G, K, L, M, N; Plan K limit $8,000; Plan L limit $4,000; high-deductible F/G $2,950; Plan N copays up to $20 (office) and $50 (ER without admission) | Medicare.gov, Compare Medigap plan benefits | 2026 plan year |
| High-deductible Plan F, G and J deductible $3,050 | CMS, F, G & J Deductible Announcements, CY2027 | 2027 plan year |
| Part B deductible $283 | CMS, 2026 Medicare Parts A & B Premiums and Deductibles | 2026 plan year |
| Medigap Open Enrollment Period: 6 months from the first month you are 65 and enrolled in Part B | Medicare.gov, When can I buy Medigap? | Federal rule, checked October 19, 2026 |
| South Dakota: six-month open enrollment at 65 regardless of health; six-month open enrollment for under-65 disability enrollees from Part B enrollment; Medicare Select offered by some companies; policies must cover deductible changes | South Dakota Division of Insurance, Medicare Supplement Policies | Fetched October 19, 2026 |
| Medicare Advantage trial right: drop the plan within 12 months of first joining | Medicare.gov, Special Enrollment Periods | Current, checked October 19, 2026 |
Official sources
- Medicare.gov: Compare Original Medicare & Medicare Advantage
- Medicare.gov: Compare Medigap plan benefits
- Medicare.gov: When can I buy Medigap?
- Medicare.gov: Special Enrollment Periods
- CMS: Final CY2026 Part C Bid Review Standards
- CMS: Final CY2027 Part C Bid Review Standards
- CMS: CY2027 Medigap high-deductible F, G and J announcement
- South Dakota Division of Insurance: Medicare Supplement Policies
- South Dakota Division of Insurance: Consumer information
How this guide is made: the Big Sioux Benefits Data Desk writes from official sources and checks each figure against the page it cites. This is general education, not advice about your situation. Plan details vary; confirm costs and coverage with Medicare.gov, the agency named above, or a licensed agent.
- Medigap vs Medicare Advantage in Sioux Falls (2026) Our newsroom article with local plan data.
- What is the difference between Medicare Advantage and Medigap? The one-question answer page.
- Does South Dakota have a Medigap birthday rule?
- HMO vs PPO in Sioux Falls
- Plan comparison How Big Sioux Benefits can help.
- Medicare Advantage plans How Big Sioux Benefits can help.
- Medicare Supplement plans How Big Sioux Benefits can help.
- All guides in the learning center