Newsroom · Sioux Falls

Switching From Medicare Advantage Back to Original Medicare: Your 2026-2027 Guide

The clock on your way back to Original Medicare isn't the one on the wall — it's the one that started ticking the day you first joined Medicare Advantage.

Yes — you can switch from a Medicare Advantage plan back to Original Medicare, but the window that actually protects your wallet is narrower and stranger than most people expect, and it is not the window most people assume. This guide walks through the three real doors back to Original Medicare, the 12-month trial right that runs on your own personal calendar, what happens to your drug coverage the moment you switch, the 63-day Medigap deadline that decides whether you get your old supplement back without a health question, and the Sioux Falls network problem that starts most of these conversations in the first place.

Every rule below comes from a source fetched directly for this article — Medicare.gov's own enrollment-period guidance, KFF's reporting on Medigap access, and CMS's 2027 Part D bid-amount fact sheet — plus the CMS PY2026 Minnehaha County plan landscape already verified in our data desk. No invented numbers, no "call for details."

Can you actually switch back to Original Medicare?

Yes, and the reason this question gets asked so often is that Medicare Advantage marketing rarely mentions the return trip. Once you're enrolled in a Medicare Advantage plan — the private, CMS-approved alternative to Original Medicare that usually bundles hospital, medical, and often drug coverage under one card — you are not locked in permanently. Federal rules give every enrollee at least two chances a year to leave, plus a special one-time protection if this is your first Medicare Advantage plan ever.

What trips people up isn't whether they can switch back — it's when, and what switching back does and doesn't automatically fix. Original Medicare on its own has no drug coverage and no cap on what you can owe in a bad year. Getting the switch right means understanding three separate clocks running at once: the enrollment window, the Part D coverage gap, and the Medigap guaranteed-issue deadline.

A quick note on the words this guide leans on, since Medicare's vocabulary is its own small language: Original Medicare is Parts A (hospital) and B (medical) as run directly by the federal government, with no private plan in between. A network is the specific list of doctors, clinics, and hospitals a private plan has contracted with — care outside it can cost more or not be covered at all. A formulary is a drug plan's list of covered medications, organized into cost tiers. MOOP stands for maximum out-of-pocket — the yearly ceiling on what a plan can make you pay. An Annual Notice of Change (ANOC) is the letter every plan sends each fall listing what's different for the coming year. Guaranteed issue means an insurer must sell you a policy regardless of health history; medical underwriting is the opposite — the insurer can ask health questions and price or deny coverage based on the answers. We define each again where it matters most below, so nothing here depends on memorizing this list first.

Why people actually make this switch

Almost nobody sets out to leave a Medicare Advantage plan on principle. The requests we hear tend to cluster around a handful of concrete, specific moments — the plan looking fine on paper right up until it stopped matching real life:

• A doctor turns out to be out of network. The plan's premium looked good during the Annual Enrollment Period; the specialist referral in February gets denied because the clinic isn't in the network after all.
• A prior authorization or referral requirement slows down care. Medicare Advantage plans can require approval before certain services, tests, or specialist visits; Original Medicare generally does not.
• A snowbird or frequent traveler realizes the network is local. Someone splitting time between Sioux Falls and a winter home outside the plan's service area finds routine care away from home costs far more, or isn't covered at all outside emergencies.
• The plan's benefits or network shrank at the Annual Notice of Change. A dental, vision, or provider change that looked minor on the cover letter turns out to matter once it's the beneficiary's own dentist or cardiologist.
• Someone simply feels rushed into the original decision. A phone call during the last Annual Enrollment Period, a mailer that looked like a government notice, or advice from someone who wasn't a licensed local agent — and a nagging sense the plan was chosen for the reader, not with them.

None of these reasons require special justification to act on. What they do require is knowing which of the three doors below is actually open on the day you're reading this.

The three doors back to Original Medicare

Depending on your situation, one of three federal enrollment mechanisms applies. Only one of them is available to everyone, every year, with no conditions attached.

Source: Medicare.gov — Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods & Medicare.gov — Open Enrollment.

The Annual Enrollment Period is the widest door — open to anyone with Medicare, for any reason, no explanation required. The Medicare Advantage Open Enrollment Period is narrower: it only opens for people already in a Medicare Advantage plan, allows exactly one change, and that change takes effect the first of the following month rather than immediately. Miss both of those windows outside a qualifying life event, and you're waiting for the next one — unless the third door applies to you.

Other Special Enrollment Periods that can open a door early

Beyond the trial right, a handful of qualifying life events can open a Special Enrollment Period (SEP) — a window created by a specific change in your circumstances, separate from the calendar-based AEP and OEP. None of these require you to be a first-time Medicare Advantage enrollee:

Source: Medicare.gov — Special Enrollment Periods.

If none of these apply and you're outside both AEP and the January–March OEP, and your personal trial right has already expired or was already used, your honest answer is to wait for the next Annual Enrollment Period. That's not the answer anyone wants mid-year, but it's the accurate one — and it's exactly the kind of question worth a five-minute call rather than guessing.

The 12-month trial right nobody explains clearly

Here's the detail that catches even careful readers: the trial right is not a calendar-year window like AEP or the January–March OEP. It is tied to the date you personally first enrolled in any Medicare Advantage plan, and it runs for exactly 12 months from that date — or until you disenroll, whichever comes first.

If you turned 65 in March 2026 and joined a Medicare Advantage plan for the first time that month, your trial right runs through roughly March 2027 — regardless of whether that stretch crosses one AEP, one OEP, or neither. Medicare.gov describes this special enrollment period as available to someone "trying" Medicare Advantage for the first time, allowing a one-time return to Original Medicare "at any time" within that first year, not just during the standard windows.

Source: Medicare.gov — Understanding Medicare Advantage & Medicare Drug Plan Enrollment Periods & Medicare.gov — Special Enrollment Periods.

This right applies only once, and only to your first Medicare Advantage plan ever. If you've already used it — or if this isn't your first Medicare Advantage enrollment — you're back to relying on AEP, the January–March OEP, or a qualifying Special Enrollment Period.

What Original Medicare alone doesn't cap

This is the piece that gets lost in the relief of finally being free of a network problem: Medicare Advantage plans are required by federal rule to carry an annual out-of-pocket maximum (MOOP) — a hard ceiling on what you pay in a calendar year for covered medical care. Original Medicare, on its own, has no such ceiling. Every dollar of Part B's 20% coinsurance keeps applying no matter how high your bills climb in a bad year.

Here's the specific exposure, using CMS's own published 2025 Medicare Parts A & B cost-sharing figures (the same rails Medigap plans are built to close):

Source: CMS 2025 Medicare Parts A & B Premiums and Deductibles (Fact Sheet).

A "benefit period" is Medicare's own term for a stretch of hospital or skilled nursing care that starts the day you're admitted and doesn't officially end until you've been out of the hospital and any skilled nursing facility for 60 days straight. Two separate hospitalizations in the same year, more than 60 days apart, mean two separate $1,736 deductibles — a detail that surprises people used to thinking of deductibles as an annual, once-a-year cost.

This is the real reason most people who switch back to Original Medicare pair it with a Medigap supplement rather than going without one. Medigap plans are specifically standardized to absorb this exact uncapped exposure — Plan G, for example, covers the Part A coinsurance and hospital costs, the Part B coinsurance, and Part B excess charges in full, per CMS's standardized Medigap benefit chart. Going with Original Medicare alone, with no Medigap and no Medicare Advantage MOOP, means carrying that uncapped 20% yourself.

What happens to your drug coverage the day you switch

Original Medicare — Parts A and B — covers hospital and medical care. It does not cover prescription drugs. If your Medicare Advantage plan included Part D drug coverage (most do), leaving that plan means your drug coverage ends on the same date your medical coverage reverts to Original Medicare, and nothing replaces it automatically.

You have to actively enroll in a stand-alone Part D prescription drug plan yourself, in the same window you use to leave Medicare Advantage. Skip this step, or leave too large a gap between your old drug coverage ending and new drug coverage starting, and you risk a penalty that follows you for the rest of the time you have Part D.

Source: Medicare.gov — How much does Medicare drug coverage cost.

The 63-day Medigap window: no health questions, if you're on time

If you had a Medigap (Medicare Supplement) policy before you tried Medicare Advantage and dropped it to switch, federal law gives you a guaranteed-issue right to get that same policy back from the same insurer — no medical underwriting, no denial for a pre-existing condition — as long as you act inside the trial right and apply within the guaranteed-issue window.

KFF's research on Medigap access describes the deadline plainly: beneficiaries generally have 63 days to apply for a Medigap policy once a guaranteed-issue event occurs, and someone who disenrolls from their first Medicare Advantage plan within the 12-month trial period keeps "guaranteed issue rights to purchase any Medigap policy that is sold in their state" — not only their old one.

Source: KFF — Medigap May Be Elusive for Medicare Beneficiaries with Pre-Existing Conditions. (This 63-day figure is corroborated once, via KFF; we did not find a second independently fetchable primary-source page with the exact number this session, so treat it as single-sourced and confirm your personal deadline with your Medigap insurer or SHIINE before relying on it.)

Source: CMS — Choosing a Medigap Policy (Publication 02110), standardized plans per 42 CFR §403.205.

What happens if you miss the window

Outside a guaranteed-issue event, Medigap insurers are legally allowed to medically underwrite an application — meaning they can ask about your health history, charge a higher premium based on it, or decline to sell you a policy at all. KFF's reporting is direct about the consequence: insurers "may use medical underwriting to either deny Medicare beneficiaries a policy or charge higher premiums outside of guaranteed issue periods."

South Dakota's baseline consumer protections, according to the state Attorney General's office, center on the standard six-month Medigap open enrollment period that starts when you first turn 65 and enroll in Part B — plus a 30-day free-look period to return a policy, and a rule that pre-existing condition exclusions can last no longer than six months. We did not find a separate state rule creating an annual or continuous guaranteed-issue window beyond those federal minimums, which is exactly why the 63-day trial-right deadline matters as much as it does here: for most people who leave Medicare Advantage after their first year, it's the one door, not one of several.

Source: South Dakota Attorney General — Medicare Supplement Insurance.

This is the part of the decision that deserves the least rushing, not the most. Someone managing diabetes, a cardiac condition, or another chronic diagnosis has the most to lose from missing a guaranteed-issue window, since those are exactly the conditions medical underwriting exists to price around. It's also exactly why this guide leads with timing rather than with the switch itself — the decision to leave Medicare Advantage and the decision about how to time the paperwork are really two separate decisions, and getting the second one wrong can undo the benefit of getting the first one right.

The Part D penalty, worked out in dollars

The Part D late enrollment penalty formula is simple, but its size depends entirely on how long the coverage gap runs. Medicare.gov puts the 2026 national base beneficiary premium — the figure the penalty is calculated against — at $38.99, and CMS's own 2027 bid-amount fact sheet lists $41.33 for 2027. The penalty itself is 1% of that figure per full month without creditable drug coverage, rounded to the nearest $0.10, added to your monthly Part D premium for as long as you're enrolled in Part D — not for one year, and not until you "pay it off."

Calculated at 1% of the 2027 national base beneficiary premium ($41.33) per uncovered month. Source: Medicare.gov — How much does Medicare drug coverage cost & CMS — Medicare Part D 2027 National Average Monthly Bid Amount Information.

A 6-month gap — easy to rack up if you assume drug coverage "carries over" when it doesn't — adds roughly $2.48 a month to your Part D premium for 2027, forever. A 2-year gap adds close to $9.92 a month, permanently. Neither number sounds catastrophic in isolation; both are entirely avoidable by enrolling in a stand-alone Part D plan the same week your Medicare Advantage coverage ends.

Original Medicare's own cost-sharing is worth naming plainly here too, since it's the reason most people pair a switch back with a Medigap policy rather than going bare: a $1,736 Part A deductible per benefit period (not per year), and 20% Part B coinsurance with no annual ceiling under Original Medicare alone.

Source: CMS 2025 Medicare Parts A & B Premiums and Deductibles (Fact Sheet).

Why Sioux Falls switch-backs usually start with a network problem

Nationally, people leave Medicare Advantage plans for all kinds of reasons. Locally, one reason shows up more than any other in our conversations: someone enrolls, then discovers a specialist, clinic, or hospital they use isn't actually in the plan's network. Sioux Falls care runs through two competing systems, and a plan's network is your bridge to one, the other, or both:

Source: CMS Hospital Compare — Overall Star Ratings.

Here's the 2026 baseline for Minnehaha County's five standard Medicare Advantage PPOs — the plans a switch-back decision is usually being weighed against:

Source: CMS Medicare Advantage / Part D Landscape (PY2026) & CMS Medicare Advantage & Part D Star Ratings (2026), Minnehaha County. All five sit at Average (3.5★) on CMS's own published scale.

Worth naming directly: a plan reaching 5 stars overall qualifies for its own year-round Special Enrollment Period under CMS rules, but none of Minnehaha County's five standard PPOs currently carry a 5-star overall rating — so that particular SEP isn't a live option for switching within Sioux Falls this plan year. It's a detail worth checking again each year, since star ratings shift with the annual measurement cycle described in our star ratings guide.

Source: Medicare.gov — Special Enrollment Periods & CMS Medicare Advantage & Part D Star Ratings (2026).

Consider a composite, illustrative example built from the pattern we see most often locally: a 67-year-old in Brandon enrolls in a Medicare Advantage PPO during her first Annual Enrollment Period, drawn by the $0 premium. Eight months in, her longtime Avera-based cardiologist sends a letter saying the practice is dropping out of that plan's network for the coming year. She's still within her 12-month trial right. Because she never carried a Medigap policy before trying Medicare Advantage, she doesn't have an "old" policy to reclaim — but she still keeps her guaranteed-issue right to buy any Medigap policy sold in South Dakota, without health questions, as long as she applies within 63 days of her Medicare Advantage coverage ending. That's the trial right doing its intended job: giving a first-time enrollee a real, no-penalty way back out.

Original Medicare with a Medigap supplement sidesteps the network question entirely — any provider who accepts Medicare, nationwide, is in-network by definition. That's a real reason some people switch back permanently, and a real reason others stay on Medicare Advantage: the trade is a wider network for a monthly Medigap premium, versus a narrower network for often little or no plan premium. We walk through that trade-off in detail in our Medigap vs. Medicare Advantage guide and our Sanford vs. Avera network breakdown.

How to actually do it: the step-by-step method

None of the six steps below require paying anyone. This is the same sequence a licensed agent walks through with a client — it's just as usable on your own kitchen table.

1. Confirm which door is open. Check today's date against AEP (Oct 15 – Dec 7), the January–March OEP, and your personal 12-month trial-right anniversary — the date you first joined any Medicare Advantage plan, not today's calendar year. If none apply, check the Special Enrollment Period table above before assuming you have to wait.
2. Decide on Original Medicare alone, or Original Medicare plus Medigap. Revisit the uncapped exposure described above before deciding to go without a supplement. If you want Medigap and you're inside your trial right, this is the moment that guaranteed-issue right is worth using — it may not come back once the 12 months close.
3. Enroll in a stand-alone Part D plan the same week your Medicare Advantage drug coverage ends. Compare plans using Medicare.gov's plan finder against your actual drug list, not just the lowest premium — a cheap Part D plan with your specific drugs on a high tier can cost more overall than a slightly higher-premium plan with better formulary placement.
4. Apply for your Medigap policy within 63 days of your Medicare Advantage coverage ending, in writing, keeping a copy of the application date. If you're using the trial right's guaranteed-issue protection, say so explicitly on the application — insurers process guaranteed-issue applications differently than standard ones, and the paperwork should reflect which one you're submitting.
5. Call Medicare (1-800-MEDICARE) or use Medicare.gov's plan finder to formally disenroll from your Medicare Advantage plan and confirm your Original Medicare reversion date in writing. Ask directly for the exact date your Medicare Advantage coverage ends and your Original Medicare coverage resumes — the two should line up exactly, with no gap in medical coverage.
6. Keep every letter and confirmation number. If a guaranteed-issue application is ever questioned by an insurer, your own paper trail — the disenrollment confirmation, the Part D enrollment date, and the Medigap application date — is your strongest evidence you acted inside the window.

How we help

You can do every step above yourself, and plenty of people do. Where a local advisor tends to save the most time is confirming which of the three doors is actually open for your specific enrollment history, matching a stand-alone Part D plan to your exact drug list so there's no coverage gap, and timing the Medigap application inside the 63-day window with paperwork that holds up if it's ever questioned.

Big Sioux Benefits can sit down with your enrollment date, your drug list, and your doctors, and map out whether switching back — and which Medigap plan, if any — actually fits your situation, at no cost to you; carriers pay licensed agents, not the other way around.

Free, unbiased counseling is also available through South Dakota Dept. of Human Services — SHIINE, South Dakota's federally funded SHIP program.

What to watch

1. Mark your own trial-right anniversary — 12 months from your first-ever Medicare Advantage enrollment date, not January 1.
2. Never let Part D coverage lapse past 63 days — enroll in a stand-alone plan the same week you leave Medicare Advantage.
3. Apply for Medigap within 63 days of your Medicare Advantage coverage ending if you want the guaranteed-issue right.
4. Confirm your specific doctors and hospital — Sanford or Avera — before assuming Original Medicare alone solves a network problem; Medigap is what removes network limits, not Original Medicare by itself.
5. Keep every enrollment confirmation and application date in one place.

How we know all this: Big Sioux Benefits runs every article through a data desk that cross-references Medicare.gov's own enrollment-period publications, KFF's Medigap research, CMS's Part D bid-amount fact sheets, the South Dakota Attorney General's consumer guidance, and the CMS PY2026 Minnehaha County plan landscape — built by Strategic AI Architects. This is education, not advice; confirm your own enrollment dates and options with Medicare.gov, 1-800-MEDICARE, SHIINE, or a licensed agent. We take no payment from any carrier to feature a plan.