How to Switch Medicare Plans
How to Switch Medicare Plans
Switching Medicare plans is one of the most important healthcare and financial decisions a retiree makes each year — and one that most people approach without enough information to make it confidently. Medicare is not a static program. Plans change every year. Premiums increase or decrease. Formularies are restructured, sometimes dramatically. Carrier networks shift, and a physician or specialist who was in-network last year may not be this year. A plan that was the right choice at 65 may be a poor fit at 72, when utilization patterns, prescription needs, and income levels have all changed. The question every Medicare beneficiary should be asking each fall is not “should I switch?” but “have I verified that staying is still the right choice?” Those are very different questions, and the distinction matters — because staying without reviewing is just as much a decision as switching, with the same potential for unintended financial consequences.
Before any switching decision can be made intelligently, the beneficiary needs to understand the structural difference between what they currently have and what they are considering. Medicare Advantage and Medicare Supplement (Medigap) are fundamentally different approaches to supplementing Original Medicare — different premium structures, different network arrangements, different cost-sharing mechanics, and different underwriting implications when switching between them. Our resource on Medicare Advantage vs Medicare Supplement comparison covers those structural differences side by side. For beneficiaries who want to understand the underlying Medicare framework before evaluating any plan change, our resource on how Medicare works provides that foundation, and our resource on Medicare Part B explained covers the coverage layer that most plan switching decisions are built around.
At Diversified Insurance Brokers, Tonia Pettitt, CMIP©, brings more than 40 years of Medicare planning experience to every client conversation. Tonia guides retirees through the enrollment periods, underwriting implications, formulary comparisons, and carrier evaluations that determine whether a plan switch is the right move — and if so, how to execute it without creating a coverage gap or triggering a penalty. The goal is not to switch plans for its own sake. The goal is to ensure that the plan you are on is the most efficient, cost-effective, and clinically appropriate structure for where you are today — not where you were when you first enrolled.
When You Can Switch Medicare Plans — The Enrollment Windows That Matter
| Period | When It Runs | What You Can Do | When Changes Take Effect |
|---|---|---|---|
| Annual Election Period (AEP) | October 15 – December 7 each year | Switch between Advantage plans; move from Advantage to Original Medicare; enroll in or change Part D; move from Original Medicare to Advantage | January 1 of the following year |
| Medicare Advantage Open Enrollment | January 1 – March 31 each year | Switch from one Advantage plan to another; disenroll from Advantage and return to Original Medicare plus Part D; cannot newly enroll in Advantage from Original Medicare | First day of the month after election is processed |
| Initial Enrollment Period (IEP) | 7-month window around 65th birthday (3 months before, month of, 3 months after) | Enroll in Part B, Part D, Medicare Advantage, or Medicare Supplement; guaranteed issue rights apply for Medigap during this window | Varies by when in the window enrollment occurs; see enrolling in Medicare at 65 |
| Special Enrollment Periods (SEPs) | Triggered by qualifying life events — no fixed calendar window | Varies by SEP type; triggers include moving out of plan service area, losing employer coverage, qualifying for Extra Help, relocating to a new state | Typically the first of the month following the qualifying event; see Medicare Part B penalties and SEPs |
Switching From Medicare Advantage to Medicare Supplement — The Most Critical Transition
Moving from Medicare Advantage back to a Medicare Supplement is the direction that carries the most risk and requires the most advance planning. During your Initial Enrollment Period at 65, you have guaranteed issue rights — Medigap insurers must accept you regardless of health history. Once that window closes, in most states the insurer can require full medical underwriting. Your health history is reviewed, and if you have significant conditions — diabetes, heart disease, cancer history, COPD, or other chronic diagnoses — you may be rated up, excluded from certain plans, or declined entirely. This is not a technicality or a rare edge case. It is a realistic scenario for many beneficiaries who enrolled in Medicare Advantage at 65 when they were healthier and now want to switch to a Supplement at 72 or 75 when they have a more complex medical history.
The critical rule: never cancel or disenroll from your Medicare Advantage plan until you have received written approval for the Medigap plan you intend to replace it with. Disenrolling first — even with full intent to replace — can leave you in a coverage gap during the underwriting review period. The sequence must be: apply for Medigap, receive written approval, then disenroll from Advantage. Our resource on best Medicare Supplement plans for seniors covers what to look for when evaluating Medigap options, and our resource on when Medicare open enrollment is covers the timing windows that govern when Supplement changes can be made. For beneficiaries who want to understand all the enrollment mistakes that can affect both switching direction, our resource on Medicare enrollment mistakes to avoid covers the full list of traps that derail otherwise straightforward plan changes.
Prescription Drug Coverage — The Most Common Reason Beneficiaries Switch
Formulary changes are the single most common reason Medicare beneficiaries need to reassess their coverage each year — and the most commonly overlooked one. A medication that was covered at Tier 1 or Tier 2 last year can move to Tier 3 or Tier 4 at the next plan year, tripling or quadrupling the out-of-pocket cost for the same drug. Carriers are not required to notify beneficiaries personally about formulary tier changes; the Annual Notice of Change (ANOC) discloses them, but most beneficiaries do not read it carefully. Our resource on what the Medicare Annual Notice of Change is covers what the ANOC contains and what to look for when reviewing it each fall.
The correct comparison process for prescription drug coverage is not premium-to-premium — it is total projected annual cost across all medications at current dosages, including monthly premium, any applicable deductible, and the expected cost-sharing for each drug at its tier. A plan with a $20 lower monthly premium can cost hundreds or thousands more per year if it places your highest-cost medication at a higher tier or requires prior authorization that delays access. Our resource on Medicare Part D donut hole covers the coverage gap mechanics that affect high-cost drug users, and our resource on getting a second opinion on your Medicare quote covers the independent comparison process that ensures no better option is being overlooked before you commit to a plan for the next year.
IRMAA and Income — How Medicare Premium Brackets Affect the Switching Decision
Medicare premiums are not flat. Beneficiaries whose income exceeds certain thresholds pay more for Part B and Part D through Income-Related Monthly Adjustment Amounts (IRMAA), and the thresholds are indexed to prior-year income — meaning a high-income year two years ago can affect your Medicare premiums today. Our resource on what IRMAA is covers how the brackets work and what options exist to appeal or manage them. Our resource on how modified adjusted gross income affects Social Security and Medicare covers the interaction between retirement income sources and Medicare premium calculations that many beneficiaries do not anticipate.
IRMAA exposure changes the economics of the Medicare Advantage versus Medicare Supplement comparison. A beneficiary paying higher Part B premiums due to IRMAA is already paying more for the Part B foundation that both plan types sit on — which affects how the total premium comparison stacks up between a $0-premium Advantage plan and a higher-premium Supplement. Understanding how retirement income decisions interact with Medicare premium brackets is part of the complete switching analysis, not a separate question. Our resource on how Medicare and Social Security work together covers that coordination, and our resource on key retirement considerations provides the broader planning context in which Medicare switching decisions typically live.
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Frequently Asked Questions: How to Switch Medicare Plans
When can I switch Medicare plans?
Most Medicare plan changes happen during the Annual Election Period (AEP), which runs from October 15 through December 7 each year. Changes made during AEP take effect January 1. The Medicare Advantage Open Enrollment Period (January 1 through March 31) allows beneficiaries already in an Advantage plan to switch to another Advantage plan or return to Original Medicare — but does not allow someone on Original Medicare to newly enroll in Advantage. Special Enrollment Periods are available outside these windows for beneficiaries who experience qualifying life events: moving out of the plan’s service area, losing employer coverage, qualifying for Extra Help, or relocating to a new state. Medicare Supplement switching is handled differently — Medigap plans can be changed at any time the carrier will approve you, but outside your initial enrollment window, medical underwriting typically applies. Understanding which window applies to your specific situation is the first step before initiating any change. Our resource on when Medicare open enrollment is covers all of the windows in detail.
Can I switch from Medicare Advantage to Medicare Supplement at any time?
Yes — but in most states, medical underwriting applies outside your Initial Enrollment Period, which means the insurer can review your health history and decline coverage or charge a higher premium based on pre-existing conditions. The guaranteed issue rights that applied when you first enrolled at 65 do not carry over indefinitely. Certain situations trigger a right to guaranteed issue Medigap coverage outside the IEP — for example, if your Medicare Advantage plan leaves your service area, or if you enrolled in Advantage for the first time and are within the first year — but these are specific exceptions, not the general rule. The practical implication: apply for and receive written approval for the Medigap plan before you disenroll from your Medicare Advantage plan. Never cancel Advantage coverage first and then apply — the gap during underwriting review is a real risk. Our resource on best Medicare Supplement plans for seniors covers the plan options to evaluate before making this switch.
What is the most important thing to review when switching Medicare plans?
Total projected annual cost — not monthly premium alone. The premium is only one component of what you will actually spend. A Medicare Advantage plan with a $0 monthly premium can produce thousands of dollars in out-of-pocket costs if it has high copays for specialist visits, hospitalizations, or outpatient procedures, or if frequent medical utilization applies. A Medicare Supplement with a $180 monthly premium can be the lower total-cost option for a beneficiary with ongoing medical needs because the Supplement covers the cost-sharing that the Advantage plan passes to the enrollee. The correct comparison includes: monthly premium for the plan and Part D (if separate), expected drug costs based on your specific medications and the plan’s formulary, and estimated out-of-pocket exposure based on your realistic utilization pattern. Prescription drug coverage deserves particular attention — formularies change annually and a medication that was inexpensive last year can move to a significantly higher cost tier at the next plan year. Our resource on what the Medicare Annual Notice of Change is covers how to read the ANOC that discloses formulary and benefit changes each fall.
What is IRMAA and how does it affect my Medicare plan decision?
IRMAA stands for Income-Related Monthly Adjustment Amount — a surcharge added to Part B and Part D premiums for beneficiaries whose income exceeds certain thresholds. IRMAA is calculated based on income from two years prior, meaning a high-income year (a business sale, a large Roth conversion, a significant capital gain) can increase your Medicare premiums two years later. In 2025, IRMAA surcharges add between $69.90 and $419.30 per month to the standard Part B premium depending on income tier. For beneficiaries subject to IRMAA, the economics of Medicare Advantage versus Medicare Supplement look different than for beneficiaries at standard premium levels, because the IRMAA cost applies regardless of which plan type you choose — it is a Part B cost, not a plan-level cost — and affects how the total premium comparison stacks up. Our resource on what IRMAA is covers how the brackets are calculated and how to appeal if your income has decreased since the assessment year. For beneficiaries planning significant income events, understanding how those events interact with Medicare premium brackets two years later belongs in the financial planning conversation, not discovered at enrollment.
What happens if I miss the enrollment deadline to switch plans?
Missing the Annual Election Period typically means you remain on your current plan for another year — you cannot make most changes outside the designated windows unless you qualify for a Special Enrollment Period. For Part D specifically, late enrollment or gaps in coverage can trigger a permanent penalty added to your monthly Part D premium for as long as you have Part D coverage. The penalty is 1% of the national base beneficiary premium for each month you were without creditable drug coverage, and it compounds over time — a two-year gap becomes a 24% permanent premium increase. Switching from Medicare Advantage to a Medicare Supplement is not subject to the same late enrollment penalties, but the underwriting risk described above applies. Missing your chance during a guaranteed issue window — whether at initial enrollment or during a qualifying SEP — is the more consequential timing error for Medigap. Our resource on how to avoid Medicare late enrollment penalties covers both Part B and Part D penalty structures that beneficiaries need to understand before making any plan change.
About the Author:
Tonia Pettitt, CMIP©, (NPN 14374308), is a seasoned Medicare specialist with more than 40 years of hands-on experience guiding individuals and families through the complexities of Medicare planning. As a senior advisor with the nationally licensed independent agency Diversified Insurance Brokers, Tonia provides clear, dependable guidance across all areas of Medicare—including Medicare Advantage, Medicare Supplement (Medigap), and Part D prescription coverage. Leveraging active contracts with dozens of highly rated insurance carriers, she helps clients compare options objectively and secure the most suitable coverage for their health and budget.
Known for her patient, education-first approach, Tonia has built a reputation as a trusted resource for retirees seeking reliable, unbiased Medicare support. With four decades of experience across evolving Medicare laws, carrier changes, and plan structures, she brings unmatched insight to every client conversation—ensuring clients feel confident, protected, and fully prepared for each stage of their retirement healthcare journey.
Explore More Medicare Options: Browse our complete guide to Enroll in Medicare at 65 — covering when to sign up, avoiding penalties, open enrollment, switching plans & key deadlines.
Last Reviewed: June 13, 2026 |
Reviewed by: Tonia Pettitt, CMIP©
Medicare Specialist, Diversified Insurance Brokers, Inc. | NPN: 14374308 | Diversified Insurance Brokers, Inc. — Licensed in all 50 states
Fact Checked by: Jason Stolz, CLTC, CRPC, DIA, CAA
Chief Underwriter, Diversified Insurance Brokers, Inc. | NPN: 20471358 | Diversified Insurance Brokers, Inc. — Licensed in all 50 states
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