Medicare Advantage

What’s Changing in South Dakota Medicare Advantage for 2027: 10 Plans Leaving, 11 Changing

SIOUX FALLS — South Dakotans on Medicare Advantage will see a reshuffled menu of plans for the 2027 plan year, according to the Centers for Medicare & Medicaid Services (CMS) Medicare Advantage Landscape Source Files for CY2026 and CY2027. Statewide, 27 Medicare Advantage plans were offered in South Dakota for 2026 and 28 are offered for 2027 — a net change of one, but with substantial churn underneath that number.

What the statewide numbers mean

In CMS's Landscape files, each plan is counted once statewide, no matter how many counties it serves. For South Dakota, the year-over-year comparison shows 27 Medicare Advantage plans for 2026 and 28 for 2027. Within that count, 10 plans are leaving — meaning they were offered somewhere in South Dakota for 2026 and nowhere in South Dakota for 2027. Another 11 plans are listed in both years but differ on at least one of the fields CMS tracks in the Landscape file: premium, drug deductible, plan type, or plan name. CMS calls those "changing." A further 6 plans continue unchanged on those fields, and 11 are new for 2027.

One carrier, Wellmark Advantage Health Plan, has no South Dakota Medicare Advantage plans listed for 2027.

Because the "changing" label is tied strictly to the fields in the CMS file, it does not describe how a plan's coverage will feel in practice. The document that spells that out is the Annual Notice of Change, mailed by each plan to its current members in the fall.

If your plan is leaving

If your 2026 plan is one of the 10 that will not be offered in South Dakota for 2027, your plan will send you a non-renewal notice. You have two protections.

First, during the Annual Enrollment Period (October 15 – December 7, 2026), you can pick a new Medicare Advantage plan or return to Original Medicare, with coverage starting January 1, 2027. Second, members of a non-renewed plan get a Special Enrollment Period that runs through the end of February, which gives you additional time to choose a new plan after the Annual Enrollment Period closes.

If you do nothing and your plan is leaving, you will not be automatically moved into another Medicare Advantage plan; coverage from the leaving plan ends, and you would default back to Original Medicare without a stand-alone Part D plan unless you act.

If your plan is changing

If your plan is one of the 11 continuing plans that CMS flags as changing for 2027, the specifics are in your Annual Notice of Change. The ANOC is required reading: it lays out exactly what is different for the coming year on the items your plan sets, including the fields CMS uses to flag a change (premium, drug deductible, plan type, name).

If you do nothing, you stay enrolled in the renewing plan with the changes described in the ANOC taking effect January 1, 2027. If you read the ANOC and decide the plan no longer fits, the Annual Enrollment Period is when you can switch.

The counties with the most change

Every one of South Dakota's 66 counties sees at least one plan leave or change. CMS's county-level counts (plans leaving / plans changing) for the counties highlighted this year:

• Douglas County: 11 leaving, 5 changing
• Lincoln County: 6 leaving, 10 changing
• McCook County: 6 leaving, 10 changing
• Miner County: 11 leaving, 5 changing
• Minnehaha County: 6 leaving, 10 changing
• Moody County: 6 leaving, 10 changing
• Turner County: 6 leaving, 10 changing
• Campbell County: 15 leaving, 0 changing

A county with a high "leaving" count does not necessarily have fewer plans overall for 2027 — new plans may enter — but it does mean more members in that county will receive non-renewal notices this fall.

What to do before December 7

A simple checklist for the weeks ahead:

1. Watch your mail in September and October for either an Annual Notice of Change (your plan is renewing) or a non-renewal notice (your plan is leaving). 2. Read the ANOC in full if your plan is renewing. The ANOC is the official source for what is different in 2027. 3. If your plan is leaving, note that your Special Enrollment Period runs through the end of February, but you can also use the Annual Enrollment Period (October 15 – December 7, 2026) to lock in January 1, 2027 coverage. 4. Compare plans available in your county using Medicare's Plan Finder before making a choice. 5. Make any change by December 7, 2026 for a January 1, 2027 start date — or use your Special Enrollment Period if your plan was not renewed.

Where to get free help

You do not have to sort this out alone, and you do not have to pay anyone to help you compare plans.

• Medicare.gov has the official Plan Finder, where you can enter your ZIP code and prescriptions to see plans available in your county.
• 1-800-MEDICARE (1-800-633-4227) is open 24/7 for questions about enrollment and coverage.
• The State Health Insurance Assistance Program (SHIP) offers free, one-on-one Medicare counseling in South Dakota. SHIP counselors are trained volunteers and staff who do not sell insurance.