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Wellmark Blue Medicare Advantage Leaving South Dakota 2027: What to Do

If you have a Wellmark Blue Medicare Advantage plan, the 2027 plan list from CMS doesn't include it. Here's what that means, the letter to watch for, and the dates that protect you.

Big Sioux Benefits Data Desk

Published September 29, 2026 · 10 min read · Sourced from CMS landscape files & Medicare.gov

CMS's 2027 plan list, published September 2026, has no Wellmark Medicare Advantage plans in South Dakota. If you're one of the people in Sioux Falls, Brandon, Tea or anywhere else in the 43 counties where Wellmark sold its Blue Medicare Advantage PPOs this year, that's the fact you need first. The second fact: you still have time, you still have choices, and there's a specific order to do things in.

Here's what we know and how we know it. We compared the two Medicare Advantage landscape files CMS publishes, one for plan year 2026 and one for plan year 2027, row by row for South Dakota. Wellmark Advantage Health Plan, contract H5900, is in the 2026 file. It isn't in the 2027 file, in any South Dakota county or any Iowa county. We looked for a public Wellmark announcement explaining why and couldn't find one, so we're not going to guess at a reason. The document that settles it for you is the letter from your plan.

A few terms, defined

• Medicare Advantage (Part C). A private plan that replaces Original Medicare for your hospital and medical coverage. Most include Part D drug coverage.
• Annual Notice of Change (ANOC). The yearly letter a plan that is coming back sends you, listing next year's changes. Our 2027 ANOC guide covers how to read one.
• Non-renewal notice. A different letter. It tells you your plan is leaving Medicare and won't exist next year.
• Special Enrollment Period (SEP). A window outside the usual calendar that opens because something happened to you, like your plan ending.
• Medigap. A supplement policy that pays some of the costs Original Medicare leaves you with. It only works with Original Medicare, not with Medicare Advantage.
• MOOP. Maximum out-of-pocket: the most a Medicare Advantage plan can make you pay for covered medical care in a year.

What changed between the 2026 and 2027 plan lists

In 2026, Wellmark Advantage Health Plan sold three Blue Medicare Advantage PPOs in 43 South Dakota counties. In CMS's 2027 landscape, none of the three appears. Here are the three 2026 plans as CMS listed them:

Source: CMS CY2026 Medicare Advantage Landscape (September 2026 release), South Dakota rows, plan year 2026. Premium figures are monthly. The Valor PPO has no drug coverage, so CMS lists no combined premium for it.

The Valor PPO is worth a separate note. It has a $0 Part C premium in 2026 and no drug coverage, which means people on Valor may get drug coverage some other way, such as a stand-alone Part D plan or coverage through the VA or an employer. When you look for a 2027 replacement, keep that setup in mind so you don't accidentally end up with two drug plans, or none.

One thing Wellmark is keeping: its MedicareBlue Rx stand-alone Part D drug plan (contract S5743) is in the 2027 CMS files. That matters if you're thinking about going back to Original Medicare and want a drug plan to go with it.

The letter to watch for

Medicare.gov says the Plan Non-Renewal Notice arrives in October, for members whose plan is leaving the Medicare program in the coming year. CMS then sends its own Non-Renewal Reminder Notice in November. If you're a Wellmark Blue Medicare Advantage member, open anything from Wellmark or Medicare this fall and read the first paragraph.

This is also why we're careful about how we phrase all this. The CMS plan list tells us which plans are on file for 2027. The notice from your plan is what confirms, in writing, what happens to your coverage, and it lists your own dates. Keep it with your Medicare card.

Sources: Medicare.gov, Plan Non-Renewal Notice; Medicare.gov, CMS Non-Renewal Reminder Notice.

Your dates: Open Enrollment and the Special Enrollment Period

If your Medicare Advantage plan isn't renewing, you have two windows to pick new coverage: Open Enrollment from October 15 to December 7, and a Special Enrollment Period from December 8 through the last day of February.

Sources: Medicare.gov, Joining a plan; Medicare.gov, Special Enrollment Periods.

Our advice is to use the first window if you can. Choosing by December 7 means your new plan starts on January 1 with no gap. The later window is a real safety net, but anything after December 31 means some time in Original Medicare first.

And if you do nothing? Medicare.gov is direct about it: "You'll be enrolled in Original Medicare if you don't join another Medicare Advantage Plan before your current plan ends." Original Medicare doesn't include prescription drug coverage. If you take any medications, you would need a separate Part D plan, and Original Medicare on its own has no yearly cap on your 20% share of Part B costs.

Your Medigap right, if you go back to Original Medicare

When a Medicare Advantage plan leaves Medicare or stops giving care in your area, and you switch to Original Medicare, you get a guaranteed issue right to buy certain Medigap policies. That comes from CMS Publication 02110, Choosing a Medigap Policy. With it, the insurance company can't turn you down or charge more because of your health.

• Which plans: Medigap Plan A, B, D or G sold in your state. Plan C or F only if you were eligible for Medicare before January 1, 2020.
• When you can apply: as early as 60 days before your Medicare Advantage coverage ends, or by the date in your plan's termination notice.
• The deadline: no more than 63 days after your Medicare Advantage coverage ends.
• The catch: this right only applies if you switch to Original Medicare. If you join another Medicare Advantage plan instead, it doesn't come into play.

Source: CMS Publication 02110, Choosing a Medigap Policy, Section 3, guaranteed issue rights.

This is a real decision, not a formality. Some people have been waiting for a chance to get into Medigap without health questions, and this is one. Others are happy with Medicare Advantage and just want a different carrier. Neither is wrong. The honest answer depends on your doctors, your drugs, your budget and how much you travel. Our non-renewal guide goes deeper on both paths.

Sioux Falls: every 2027 plan in Minnehaha County

CMS's 2027 landscape lists 14 non-SNP Medicare Advantage and Medicare Cost plans in Minnehaha County, down from 16 in 2026, and 4 of the 14 carry a $0 plan premium. Wellmark is gone from the county's list. Aetna, Medica, Sanford Health Plan and UnitedHealthcare remain. Here is every one of the 14:

Source: CMS CY2027 Medicare Advantage Landscape (September 2026 release), Minnehaha County, plan year 2027. "Monthly premium" is CMS's consolidated premium (Part C plus Part D) where the plan includes drug coverage; for plans without drug coverage it's the Part C premium. Star ratings are blank in this September 2026 file. Excludes Special Needs Plans.

A few things stand out. The Medica Prime Solution plans are Medicare Cost plans, which work differently from Medicare Advantage, and CMS's file lists their premiums differently: most show only a Part C premium, and two show no premium figure at all. Get the full monthly cost and the drug-coverage setup in writing before you pick one. Two plans on the list, the Aetna Eagle Classic and the AARP Patriot No Rx, don't include drug coverage at all. And a low premium isn't the whole story: most of these plans list a $7,150 maximum out-of-pocket, while a few are lower.

If you're in Sioux Falls, our Minnehaha County plan page and Sioux Falls plans overview have more local detail.

All 43 counties, 2026 vs 2027

Every one of the 43 counties where Wellmark sold Blue Medicare Advantage in 2026 still has at least 5 plans on CMS's 2027 list. The table below shows each county's carriers and CMS plan counts for both years. The counts are non-SNP Medicare Advantage and Medicare Cost plans from the CMS landscape files. They include plans we don't offer, and the changes in some counties reflect other carriers too, not just Wellmark.

Sources: CMS CY2026 Medicare Advantage Landscape (September 2026 release) and CMS CY2027 Medicare Advantage Landscape (September 2026 release), South Dakota rows. Plan counts exclude Special Needs Plans. Each county name links to our county page with the full plan list.

If you live in one of the counties where the 2027 list is shorter, a few plans is still a real choice. It just makes it more important to check each one against your doctors and your drugs, because there's less room to fall back on.

What to do, step by step

1. Watch for your letter in October. Open everything from Wellmark and Medicare. Keep the non-renewal notice; it has your dates.
2. Make a short list: your doctors and clinics, every prescription with its dose, and any travel you do.
3. Decide which direction you're leaning: another Medicare Advantage plan, or Original Medicare with a Medigap policy and a Part D plan.
4. Compare the 2027 options in your county. The tables above are the starting list. Check each plan's network and drug list, not just the premium.
5. Enroll by December 7 if you can, so your new coverage starts January 1 with no gap. The December 8 to end-of-February window is there if you need it.
6. If you're going the Medigap route, apply inside the 60-days-before to 63-days-after window so you keep your guaranteed issue right.

The plan list tells you what changed. Your letter tells you your dates. Between the two, you have more time than it feels like, but not unlimited time.

Talking it through with us

This is the kind of fall we see every few years: a carrier people liked isn't on next year's list, and a lot of folks in Sioux Falls and across eastern South Dakota need to pick something new at the same time. We're a licensed independent agency here in Sioux Falls. We'll sit down with your letter, your drug list and your doctors, and compare the plans we offer in your county side by side. We'll also tell you plainly when something we don't offer might fit you better. There's no cost to talk.

If you'd rather start on your own, Medicare's Plan Finder on medicare.gov lets you compare plans against your drug list. Our Medicare & You 2027 guide explains the handbook that's arriving this fall, too.

How we know all this: Big Sioux Benefits runs every article through a data desk that reads primary sources directly. For this one, that means the CMS CY2026 and CY2027 Medicare Advantage landscape files (September 2026 releases), compared row by row for South Dakota, plus Medicare.gov's pages on Special Enrollment Periods, Open Enrollment and plan non-renewal notices, and CMS Publication 02110. We did not find a public Wellmark announcement, and we haven't guessed at one. Built by Strategic AI Architects. This is education, not advice; confirm your own plan's status and dates with the notice from your plan, a licensed agent or Medicare.gov. 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. Big Sioux Benefits is a licensed independent insurance agency (NPN DEMO-NPN-00000000). Not connected with or endorsed by the United States government or the federal Medicare program. We take no payment from any carrier to feature a plan.