Plans & Coverage · South Dakota rules · 2026
Medicare Supplement (Medigap) Plans in South Dakota: The 2026 Rules
South Dakota sells the same federally standardized Medigap plans as the rest of the country — A, B, D, G, K, L, M, and N (C and F are closed to anyone newly eligible on or after January 1, 2020) — with three state-specific facts worth knowing: under-65 beneficiaries are guaranteed access to every plan at premiums capped at the 75-year-old rate, there is no birthday or anniversary switching rule, and free unbiased counseling comes from SHIINE, the state's SHIP program. For 2026, the high-deductible Plan G/F deductible is $2,950 (CMS, October 2025).
Page published: August 18, 2026 · Facts verified against the sources listed below on August 18, 2026
The standardized lettered plans (and the two that closed)
Federal law standardizes Medigap benefits by letter: a Plan G from one carrier covers exactly what a Plan G from any other carrier covers. Price, rate-increase history, and service are the real differences. Under the MACRA law, Plans C and F — the ones covering the Part B deductible ($283 in 2026) — cannot be sold to anyone newly eligible for Medicare on or after January 1, 2020; people eligible before that date may still buy them where offered (source: Medicare.gov, "How to compare Medigap policies").
| Plan | What it covers, in one line |
|---|---|
| A | The base set: Part A hospital coinsurance, Part B coinsurance, first 3 pints of blood, hospice cost sharing. |
| B | Plan A benefits plus the Part A hospital deductible. |
| D | Plan B benefits plus skilled-nursing coinsurance and foreign travel emergency (80%). |
| G | Everything Medigap can cover except the Part B deductible — including Part B excess charges. The most comprehensive plan open to new enrollees. Also sold as high-deductible Plan G. |
| K | Partial (50%) coverage of several gaps, with an annual out-of-pocket limit set by CMS each year. |
| L | Partial (75%) coverage of several gaps, with a lower annual out-of-pocket limit than K. |
| M | Plan D benefits but only 50% of the Part A deductible. |
| N | Plan G benefits except excess charges, with small copays for some office and ER visits. |
| C, F | Closed to those newly eligible on/after Jan 1, 2020 (MACRA); F also exists in a high-deductible version for those still eligible. |
Source: Medicare.gov — Compare Medigap plan benefits — accessed 2026-08-18. Plan K and L annual out-of-pocket limits are set by CMS each year; confirm the current-year amounts before enrolling.
What Plan G specifically pays for — including the Part A hospital deductible ($1,736 in 2026) — is broken out in our answer page: What does Medigap Plan G cover? →
When you can buy: the 6-month window, then underwriting
Your Medigap open enrollment period is the 6-month stretch that starts the first month you are both 65 or older and enrolled in Medicare Part B. During those 6 months an insurer must sell you any policy it offers, at the standard rate, regardless of your health history — and the window does not repeat (source: Medicare.gov, "When can I buy Medigap?").
After it closes, carriers in South Dakota may medically underwrite — ask health questions and decline or rate you — unless a federal guaranteed-issue right applies. The common ones: your Medicare Advantage or Cost plan leaves Medicare or your area, you move out of your plan's service area, your employer coverage ends, or you use the 12-month "trial right" after trying Medicare Advantage for the first time (source: Medicare.gov, "Guaranteed issue rights"). Timing this window well is most of the Medigap game — see When can you enroll in Medigap in South Dakota? →
The South Dakota specifics
Under 65? South Dakota guarantees you access
Federal law does not require Medigap sales to beneficiaries under 65 (typically people on Medicare through disability) — but South Dakota does. The state is listed among those making all Medigap plans guaranteed-issue for under-65 beneficiaries, with premiums capped so an under-65 enrollee cannot be charged more than a 75-year-old for the same policy. Under-65 enrollees then get a second, full open enrollment period at 65 (sources: medicareresources.org state-by-state under-65 Medigap guide, updated March 6, 2026; healthinsurance.org South Dakota Medicare guide, updated June 2026).
No birthday rule — and that's worth knowing
A growing list of states (California, Oregon, Idaho, Illinois, Nevada, Kentucky, and others — roughly 15+ as of 2026) give Medigap policyholders an annual "birthday rule" window to switch plans without health questions. South Dakota is not one of them: it appears on no current birthday- or anniversary-rule list (verified against the MedicareGuide.com state-by-state birthday-rule guide, updated July 14, 2026, and the MedicareFAQ birthday-rule guide, 2026). Practically, that means a South Dakota Medigap holder who wants to change plans outside a guaranteed-issue event should expect underwriting — so the plan you pick in your open enrollment window matters more here than in birthday-rule states. Full answer: Does South Dakota have a Medigap birthday rule? →
SHIINE — the state's free counseling program
SHIINE (Senior Health Information and Insurance Education) is South Dakota's federally funded State Health Insurance Assistance Program (SHIP), administered through the state with offices in Sioux Falls, Rapid City, and Milbank — shiine.net, 1-800-536-8197 (sources: SD Department of Human Services, dhs.sd.gov; shiphelp.org). SHIINE counselors are unbiased and sell nothing. Insurance questions about a specific carrier or policy can also go to the South Dakota Division of Insurance, the state regulator.
High-deductible Plan G: the $2,950 number for 2026
High-deductible Plan G (and, for those eligible before 2020, high-deductible Plan F) trades a much lower premium for a single annual deductible you pay before the plan pays. CMS resets that deductible every year: for calendar year 2026 it is $2,950, announced by CMS in October 2025 as a 2.92% CPI-U increase over 2025's $2,870 (source: CMS, "CY2026 Medigap High Deductible Options F, G, & J"). Until you spend $2,950 on Medicare cost sharing in the year, you pay Original Medicare's deductibles and coinsurance yourself; after it, the plan pays like a standard Plan G. Details: What is the high-deductible Plan G deductible for 2026? →
Medigap, Medicare Advantage, or a Cost plan? The South Dakota picture
South Dakota is unusual: most of its Medicare beneficiaries still use Original Medicare — often with a Medigap policy and a standalone Part D drug plan — rather than Medicare Advantage, and it is one of the few states where Medicare Cost plans remain common. Several counties (including Hughes County/Pierre) sell no standard Medicare Advantage plan at all, which makes Medigap the workhorse of western and central South Dakota. How the three differ is our most-asked question: Medicare Advantage vs. Medigap, explained →
For the Advantage side of the decision, every county and city has its own data page — see all 66 South Dakota county guides, the statewide 2026 guide, or your city's page from areas we serve. Our plain-English Medigap basics page covers how the coverage itself works. And if you get care through the Indian Health Service or a tribal health program, Medicare interacts with that system by its own set of rules — see American Indians and Medicare in South Dakota.
A note on prices: this page deliberately quotes no carrier premiums. Medigap premiums vary by carrier, age, tobacco use, and rating method, and change with rate filings — a licensed agent (or SHIINE) can quote current South Dakota rates for your situation.
South Dakota Medigap questions, answered
What Medigap plans can you buy in South Dakota?
The same federally standardized lettered plans sold nationwide: A, B, D, G, K, L, M, and N. Plans C and F are closed to anyone newly eligible for Medicare on or after January 1, 2020 under the MACRA law — people eligible before that date can still buy them where offered. Benefits are identical for the same letter regardless of carrier; only price and service differ.
When can you enroll in Medigap in South Dakota?
Your best window is the 6-month Medigap open enrollment period that starts the month you are both 65 or older and enrolled in Medicare Part B. During it, insurers must sell you any policy they offer at the standard rate regardless of health. Outside that window, you can apply any time, but carriers can medically underwrite unless a federal guaranteed-issue right applies — such as your Medicare Advantage plan leaving your area or losing employer coverage.
Can you get Medigap in South Dakota before age 65?
Yes. South Dakota is one of the states that make all Medigap plans guaranteed-issue for beneficiaries under 65 (for example, those on Medicare through disability), and state rules cap their premium at no more than what a 75-year-old pays (per the medicareresources.org and healthinsurance.org state guides, updated 2026). Under-65 enrollees also get a second full open enrollment window when they turn 65.
Does South Dakota have a Medigap birthday rule?
No. South Dakota has no birthday or anniversary switching rule. Roughly 15+ states (California, Oregon, Idaho, Illinois, and others) let Medigap policyholders switch plans around their birthday without health questions — South Dakota does not appear on any current state list (verified against 2026 birthday-rule guides). Outside your open enrollment window or a guaranteed-issue event, switching in SD generally means answering health questions.
What is the high-deductible Plan G deductible for 2026?
$2,950. CMS sets this amount annually; for calendar year 2026 it announced $2,950 for high-deductible Plans F, G, and J (October 2025 announcement, a 2.92% CPI-U increase over 2025's $2,870). You pay Medicare cost sharing up to that amount each year before the plan pays, in exchange for a much lower premium.
Where can South Dakotans get free, unbiased Medigap counseling?
SHIINE — Senior Health Information and Insurance Education — is South Dakota's federally funded State Health Insurance Assistance Program (SHIP), administered through the state at shiine.net, 1-800-536-8197, with offices in Sioux Falls, Rapid City, and Milbank. It is free and does not sell insurance. Licensed agencies like ours are also free to work with, because carriers pay the agent.
Sources and citations
- CMS — CY2026 Medigap High Deductible Options (F, G & J) — announced October 2025; accessed 2026-08-18
- CMS — 2026 Medicare Parts A & B Premiums and Deductibles — November 14, 2025; accessed 2026-08-18
- Federal Register — CY2026 Inpatient Hospital Deductible and Coinsurance Amounts — November 19, 2025; accessed 2026-08-18
- Medicare.gov — Compare Medigap plan benefits — accessed 2026-08-18
- Medicare.gov — When can I buy Medigap? — accessed 2026-08-18
- Medicare.gov — Guaranteed issue rights — accessed 2026-08-18
- medicareresources.org — Medigap eligibility for Americans under 65, by state — updated March 6, 2026; accessed 2026-08-18
- healthinsurance.org — Medicare in South Dakota — updated June 2026; accessed 2026-08-18
- MedicareGuide.com — Medigap birthday rules by state — updated July 14, 2026; accessed 2026-08-18 (South Dakota absent from every listed state)
- South Dakota DHS — SHIINE program — accessed 2026-08-18
- shiphelp.org — South Dakota SHIP (SHIINE) — accessed 2026-08-18
Big Sioux Benefits is a licensed insurance agency, not affiliated with or endorsed by the U.S. government or the federal Medicare program. We do not offer every plan available in your area. Contact Medicare.gov, 1-800-MEDICARE, or SHIINE (South Dakota's SHIP) for all of your options. This page is education, not a plan recommendation or a quote.
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