Medicare in South Dakota

Medicare enrollment in South Dakota

As of February 2026, there were 204,856 residents enrolled in Medicare in South Dakota.¹

Most people become eligible for Medicare enrollment when they turn 65 years old, but Medicare also provides coverage for disabled Americans under age 65, once they have been receiving disability benefits for 24 months or have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS). Nationwide, about 9% of all Medicare beneficiaries are under the age of 65.² In South Dakota, about 8% of Medicare beneficiaries are under the age of 65.¹

• Read about Medicare’s open enrollment period and other important enrollment deadlines.
• Learn how South Dakota’s Medicaid program can provide assistance to Medicare beneficiaries with limited income and assets.

Medicare Advantage plan availability and enrollment in South Dakota

In South Dakota in 2026, there are 15 counties where no individual Medicare Advantage plans are available. But the average Medicare beneficiary in South Dakota can choose from among seven Medicare Advantage plans in 2026.³

As of February 2026, 72,963 Medicare beneficiaries in South Dakota were enrolled in Medicare Advantage plans, amounting to about 36% of the state’s Medicare population. The rest were enrolled in Original Medicare.¹

Learn more about Medicare Advantage, Medicare’s annual open enrollment period, and the Medicare Advantage open enrollment period.

Sources: Medicare Advantage 2026 Spotlight: A First Look at Plan Offerings, KFF.org, Dec. 9, 2025; Fact Sheet: Medicare Open Enrollment for 2026, Centers for Medicare & Medicaid Services. Sep. 26, 2025

Medicare supplement (Medigap) plan availability in South Dakota

In South Dakota, 41 insurers are licensed to offer Medigap plans and are actively marketing these policies.⁴

According to an AHIP analysis, 70,435 people in South Dakota had Medigap coverage as of 2024.⁵

Unlike other Medicare plan enrollment (Medicare Advantage plans and Medicare Part D prescription drug plans), there is no annual open enrollment window for Medigap plans. Instead, federal rules provide a one-time six-month window when Medigap coverage is guaranteed-issue. This window starts when a person is at least 65 and enrolled in Medicare Part B (you must be enrolled in both Part A and Part B to buy a Medigap plan).

People who aren’t yet 65 can enroll in Medicare if they’re disabled and have been receiving disability benefits for at least two years, or if they have end-stage renal disease (ESRD) or amyotrophic lateral sclerosis (ALS) (about 8% of South Dakota Medicare beneficiaries are under age 65⁶). Federal rules do not guarantee access to Medigap plans for people who are under 65, but the majority of the states have rules to ensure that disabled Medicare beneficiaries have at least some access to Medigap plans.

In South Dakota, Medicare beneficiaries under the age of 65 have the same Medigap Open Enrollment Period as people who are gaining access to Medicare due to age.⁷ These enrollees have six months from the time they enroll in Medicare Part B to select a guaranteed-issue Medigap plan.

For South Dakota Medigap plans that base rates on the age of the enrollee (which is nearly all of them), the premiums for people under age 65 are equal to the premiums for people who are 75, because state regulations prohibit Medigap insurers from charging enrollees under age 65 more than they charge enrollees who are 75.⁸

People who are enrolled in Medicare prior to age 65 will have another Medigap Open Enrollment Period, when they turn 65, during which they can switch to a different Medigap plan and get the lower premiums that apply to people who are eligible for Medicare due to age, rather than disability.

South Dakota has an extensive list of state statutes that apply to rate and form filing requirements for Medigap plans.

Learn what Medigap covers, who’s eligible for Medigap and when you can enroll.

Medicare Part D plan availability and enrollment in South Dakota

For 2026, there are 11 stand-alone Medicare Part D prescription drug plans available in South Dakota, with premiums that start as low as $4.70 per month.⁹

As of early 2026, there were 113,083 Medicare beneficiaries in South Dakota who had coverage for prescription drugs under stand-alone Medicare Part D prescription drug plans.¹ Another 44,265 had Part D prescription coverage as part of their Medicare Advantage Prescription Drug plans (MA-PDs).¹

Although the number of South Dakota beneficiaries with MA-PD coverage is growing, it’s still a small segment of overall Part D coverage in the state. Nationwide, there are now more people with MA-PD coverage than with stand-alone Part D coverage,² but that’s not the case in South Dakota.

Learn how Medicare Part D prescription drug coverage works, what it pays for, how and when to enroll.

Source: Fact Sheet: Medicare Open Enrollment for 2026, Centers for Medicare & Medicaid Services. Sep. 26, 2025

Resources for Medicare beneficiaries in South Dakota

Got questions about filing for Medicare benefits in South Dakota? Check out these resources:

• SHIINE, South Dakota’s Senior Health Insurance Information and Insurance Education program answers questions related to Medicare eligibility in South Dakota, Medicare enrollment in South Dakota, or changing various aspects of your Medicare coverage after you’re enrolled.
• The South Dakota Department of Social Services has information about Medicare Savings Programs that are available to residents with limited income and assets. And this page provides a thorough overview of how South Dakota’s Medicaid program provides assistance to Medicare beneficiaries with limited financial means.
• The South Dakota Division of Insurance licenses, regulates, and oversees the health insurance companies that offer coverage in the state (for Medicare beneficiaries, Medigap plans are regulated at the state level), as well as the brokers and agents who sell policies. Their office can provide information and address a variety of consumer inquiries and complaints about the entities they regulate.
• The Medicare Rights Center is a nationwide service that can provide assistance and information to Medicare beneficiaries and their caregivers who have questions about Medicare eligibility, enrollment, or benefits.