Medicare Open Enrollment 2026-27: Dates, What You Can Change

Medicare's fall open enrollment is your once-a-year chance to review your health and drug coverage for the coming year. Plans change their costs, networks and benefits every year, and so do your needs — so the Annual Enrollment Period is worth using even if you are happy with your current plan. This guide covers the exact dates, what you can and cannot change, what changed for 2027, and how to make the smartest decision before the December 7 deadline.

When Is Medicare Open Enrollment 2026-27?

The Medicare Annual Enrollment Period is a fixed seven-week window every fall. For the 2026-27 cycle, the dates are locked in:

Milestone	Date
Annual Notice of Change letters mailed by plans	By September 30, 2026
Open Enrollment (AEP) begins	October 15, 2026
Open Enrollment (AEP) ends	December 7, 2026
Changes take effect	January 1, 2027
Medicare Advantage Open Enrollment (MA members only)	January 1 – March 31, 2027

What You Can Change During the AEP

• Switch from Original Medicare to a Medicare Advantage plan.
• Switch from a Medicare Advantage plan back to Original Medicare.
• Change from one Medicare Advantage plan to another.
• Join a Medicare Part D prescription drug plan.
• Switch from one Part D plan to another.
• Drop your Part D plan (though late enrollment penalties may apply later).

What you cannot do during the AEP is enroll in Medicare for the first time — that is handled by the Initial Enrollment Period around your 65th birthday or the General Enrollment Period. The AEP is for people who already have Medicare and want to adjust their coverage for the new year.

How to Review Your Coverage

Plans send every member two important documents in the fall: the Annual Notice of Change (ANOC), which explains how your plan changes for next year, and the Evidence of Coverage (EOC), which describes your full benefits. Read both before you decide. Then compare options using the Medicare Plan Finder at Medicare.gov, which lets you enter your prescriptions and see which Part D plans cover them for the best price.

Do not assume your current plan is still the best option. Premiums, copays, provider networks and pharmacy formularies all change from year to year, and a plan you were happy with in 2026 may not fit in 2027. The single most common mistake is skipping the review because "nothing changed" — the ANOC letter is there to show you exactly what did change.

What's New for 2027: CMS Rule Changes

For the 2026-27 enrollment cycle, the CMS final rule made notable changes. The agency eliminated eleven Star Ratings quality measures and reinstated a general reward factor in place of the Health Equity Index, which means some plans may show a different star rating in 2027 not because their care changed but because the scoring formula changed. CMS also loosened marketing restrictions on insurance agents and brokers effective October 1, 2026, which consumer advocates expect will increase marketing activity during this enrollment period. Understanding this context helps you compare plans on real value rather than on ratings noise.

What Happens If You Miss the December 7 Deadline?

If you do not make a change by December 7, 2026, your current coverage generally continues into 2027. However, if you are in a Medicare Advantage plan and want to adjust, you have a second, more limited chance: the Medicare Advantage Open Enrollment Period (January 1 – March 31, 2027), which allows a one-time switch between MA plans or back to Original Medicare. If you are not in an MA plan, the December 7 deadline is your only window until the next fall, unless you qualify for a Special Enrollment Period triggered by events like losing employer coverage or moving.

Medicare Enrollment Periods: Quick Reference

Period	Dates	Who and what
Annual Enrollment Period	Oct 15 – Dec 7, 2026	All beneficiaries: switch plans, Part D, Original vs MA
Medicare Advantage OEP	Jan 1 – Mar 31, 2027	MA enrollees: one-time switch to another MA plan or Original Medicare
General Enrollment Period	Jan 1 – Mar 31, 2027	People who missed their IEP: Part A and/or Part B (penalties may apply)

The Key Dates That Structure the 2026 AEP

Medicare's Annual Enrollment Period runs from October 15 through December 7, 2026, and every date in that window matters in a slightly different way. The period opens on October 15, but you do not need to enroll on day one — the full window is your runway. What you choose by December 7 takes effect on January 1, 2027, which means the decisions you make this autumn are locked in for a full calendar year. Early November adds meaningful context: CMS typically publishes its official Part A and Part B premiums, deductibles and new IRMAA brackets around mid-November, so the weeks between November 15 and December 7 are when you have the final numbers in hand before you commit.

That sequence creates a simple but powerful planning approach: use October to gather your current plan documents, prescription list and doctors, use early November to compare options knowing roughly what 2027 will cost, and reserve the December 7 deadline as the only hard date in the window. For 2027, one confirmed figure makes that planning sharper than most years: the Part D out-of-pocket cap rises to $2,400 and the Part D standard deductible rises to $700, both finalized figures that no longer depend on fall announcements.

What the AEP Can — and Cannot — Change

The AEP is powerful, but it is not everything. During the October 15 – December 7 window you can switch from Original Medicare to Medicare Advantage, or from Medicare Advantage back to Original Medicare; you can change from one Medicare Advantage plan to another; and you can join, drop or switch a standalone Part D drug plan. If you have a Medicare Advantage plan, you can also use the separate Medicare Advantage Open Enrollment Period from January through March, but that window allows only a one-time switch between Medicare Advantage plans or back to Original Medicare — it does not allow you to choose a Part D plan on its own.

What the AEP does not cover is your initial enrollment decision. The seven-month Initial Enrollment Period around your 65th birthday is when you first sign up, and the Special Enrollment Periods handle life events like losing employer coverage. A common mistake is assuming the AEP is where newly eligible people enroll — it is not, and confusing the two can delay your Part B start date or trigger the late-enrollment penalty. If you are not yet on Medicare, the AEP is a preview of options; the enrollment window you care about is the one tied to your age or your employment.

How to Compare Plans: Premiums, Formularies and Networks

Comparing Medicare plans is not a comparison of premiums alone — it is a comparison of three documents. The first is the premium, the monthly amount you pay for coverage; the second is the formulary, the list of prescription drugs the plan covers and their tiers; and the third is the provider network, only relevant for Medicare Advantage, which limits which doctors and hospitals are in-network. Two plans can carry virtually identical premiums and differ wildly on your specific drugs or your specific doctors, which is why the most important comparison is always plan against your personal usage, not plan against plan in the abstract.

Medicare's Plan Finder at medicare.gov is the tool built for exactly this. Enter your drugs and your pharmacy, and it ranks 2027 plans by your estimated total cost, including premiums, deductibles and copays. Move your preferred doctors in the plan details to flag network mismatches before you enroll. Also verify the "star rating" CMS gives each plan — the Medicare star system scores plans on quality and member experience on a five-star scale, and while a high rating is not a guarantee, it is a reasonable proxy for how the plan treats its members. The cheapest plan on paper is often not the cheapest plan for you; the Plan Finder is what turns paper comparisons into real ones.

Medicare Advantage vs. Original Medicare + Medigap

The biggest structural choice of the AEP is between two ways of carrying your Medicare benefit. Original Medicare (Part A and Part B) combined with a standalone Part D plan and, often, a Medigap supplement gives you the broadest network — any provider that accepts Medicare — with predictable 20% coinsurance on Part B services largely covered by the Medigap plan once you pay that plan's premium. Medicare Advantage replaces that package with a single private plan that must provide the same Part A and Part B coverage, typically adds dental, vision and hearing plus a drug benefit, and caps your annual out-of-pocket spending, but restricts you to the plan's network.

The trade-offs are the reason this decision deserves deliberate thought each October. Advantage plans often have lower monthly premiums and built-in extras, and in 2027 they remain popular for that reason. Original Medicare plus Medigap generally costs more per month but offers freedom of provider choice nationwide, no referrals for most services, and no network surprises — especially important if you split your time between states or travel in winter. Because a Medigap plan purchased after your initial guarantee issue window can be turned down by insurers based on your health, the timing matters: switching from Advantage to Original Medicare during the AEP does not automatically guarantee you can buy any Medigap plan at standard rates, so check your state's rules before you move.

The Part D Piece: Your Prescription Drug Plan in 2027

Every Medicare arrangement touches Part D at some level, because drug coverage is the piece where costs move fastest between years. Standalone Part D plans and Medicare Advantage plans with drug coverage both publish new formularies each fall, and plans frequently move your maintenance medications to higher tiers, change preferred pharmacies, or drop a drug entirely — changes that only show up when you read the 2027 "Annual Notice of Change" each plan mails out by the end of September. That notice is your permission to shop: your current plan is not obligated to stay the same, and you are not obligated to stay in it.

For 2027, two of the biggest drug cost features in Medicare history are already locked in. The Part D out-of-pocket cap rises to $2,400 for the year, meaning once your true out-of-pocket spending on covered drugs reaches that amount, you pay nothing more for covered prescriptions for the rest of 2027 — building on the $2,000 cap introduced in 2025 that was itself a first in the program. The standard Part D deductible rises to $700. When you compare Part D plans in the AEP, apply the $2,400 cap to your actual expected drug spending: for people with high-cost drugs, the cap can make a seemingly pricier plan the cheapest overall outcome for the year.

What's Confirmed and What's Still Projected for 2027

Distinguishing finalized figures from projections keeps your AEP decision honest. Confirmed for 2027: the Part D out-of-pocket cap ($2,400), the Part D standard deductible ($700), and the structure of the Annual Enrollment Period itself. Projected, pending the November CMS announcement: the standard Part B premium (the trustees estimate about $209.50, up from the confirmed $202.90 in 2026, with private forecasters suggesting $215 to $219), the Part B deductible, and the Part A hospital deductible. The Part B premium and IRMAA brackets you compare in November will be official; the figures you hear through the summer are estimates because the fall data update the numbers.

The practical result is a two-horizon budget. For your 2027 monthly costs, plan around a Part B premium near $209.50 to $219, and treat the difference as a small buffer rather than a surprise. For your drug costs, the confirmed cap makes planning precise — once you reach $2,400 in true out-of-pocket covered drug spending, Medicare covers everything else in the plan year. Because the cap and premium move on different timetables, you can make your Part D decision now with confidence and revisit only the premium-based pieces after mid-November.

Five Scenarios Where Switching Makes Sense in 2026

Not everyone should switch plans in an AEP, but specific situations should push you to at least compare. First, if your Part D plan moved one of your expensive drugs to a higher tier or dropped it entirely — the Annual Notice of Change will tell you this in September — you should compare alternatives within your budget. Second, if your premiums rose faster than your Social Security COLA, a lower-premium plan with the same formulary can reclaim the difference. Third, if your primary doctors are leaving your Medicare Advantage network, the AEP is your window to change plans or return to Original Medicare.

Fourth, if your income dropped because of retirement or a life-changing event, your IRMAA surcharge may no longer apply — a Form SSA-44 filed during the AEP can reduce or remove the surcharge before January, changing the true cost of your plan. Fifth, if you qualify for the Medicare Savings Program or Extra Help based on your current income, those programs can change what you pay for Part B and Part D, and enrolling through your state's Medicaid agency during the fall makes your January coverage line up correctly. In every scenario, the discipline is the same: compare on your personal data, confirm the numbers in November, and decide before December 7.

How to Enroll or Switch Before December 7

The mechanics of using the AEP are straightforward once you have made your decision. Medicare offers two enrollment routes. You can enroll online through Medicare.gov, where the Plan Finder ends with a digital enrollment form; or you can enroll by phone at 1-800-MEDICARE, or in some cases through the private plan directly using your Medicare number and the effective date you select. Switching plans works exactly the same way — enrolling in a new plan causes disenrollment from your old one automatically, with both changes taking effect January 1, 2027, so there is no gap in coverage to manage.

Three practical details smooth the process. Keep your Medicare number handy and double-check the plan name and number before submitting, because typing errors on plan IDs are a common source of back-and-forth correspondence. Save or screenshot the confirmation, since the plan cannot start billing you until the enrollment is processed. And if you enroll in the last days of November or the first week of December, leave yourself phone time — call volume to Medicare and to plans spikes in late November, and holding time can hit an hour or more. Starting early in October is the strongest hedge against that last-minute traffic.

Avoiding Scams During Open Enrollment

Open enrollment is also open season for scams, and Medicare beneficiaries are a favorite target. The cardinal rules: Medicare and legitimate plans will not call you pressuring you to act immediately, will not ask for your Medicare number or bank details over the phone, and will not charge you for "assistance" with the open enrollment process. Legitimate plan representatives can call, but they follow strict marketing rules — including not cold-calling you without a prior relationship — and they must identify the plans they are authorized to sell. Any caller demanding immediate action, offering a "free Medicare exam," or telling you your coverage is being canceled unless you pay something is a red flag.

If something feels off, hang up and call 1-800-MEDICARE directly, or report the call to the Senior Medicare Patrol for your state. Be equally careful with websites that advertise "official" Medicare enrollment but are not at medicare.gov — the real portal is the only place to enroll online officially. And never share your Medicare card photo over the phone, by text or by e-mail. The Medicare identity-theft risk is not academic: with your Medicare number and personal details, scammers can bill Medicare for false services or steal your identity entirely. Free help from your State Health Insurance Assistance Program (SHIP) exists precisely for this — neutral, free counseling with no selling involved.

Special Enrollment Periods: Your Options After December 7

If you miss the December 7 deadline, notice it before you panic: the AEP is the main annual window, but it is not the only way your Medicare coverage can change without waiting a full year. A Special Enrollment Period (SEP) covers qualifying life events — moving to a new area with different plan options, losing employer or union coverage, gaining Extra Help, moving into or out of a facility, or, in some cases, a five-star plan exemption that lets you switch to a Medicare Advantage or Part D plan rated five stars at any time. Each SEP has its own qualifying set and its own window, but the common thread is that they exist so coverage follows your life rather than your calendar.

The other fallback is narrower: if you are in Medicare Advantage, the Medicare Advantage Open Enrollment Period from January 1 to March 31 lets you change to a different Medicare Advantage plan or return to Original Medicare with a Part D plan. It does not allow moving from Original Medicare into a Medicare Advantage plan — only the AEP opens that door. Neither option resurrects a missed AEP decision about a standalone Part D plan if you simply forgot; for that, Extra Help and state programs are your realistic paths. The honest summary is that December 7 is a real deadline, but one with life-event valves around it — know which valve applies to you before assuming you are trapped until next October.

How IRMAA Affects Your 2027 Open Enrollment Choice

Income-related amounts quietly change the real cost of every plan you compare during the AEP. IRMAA — the Income-Related Monthly Adjustment Amount — adds a surcharge to Part B and Part D premiums for beneficiaries whose modified adjusted gross income from two years earlier (so, for 2027, your 2025 tax return) exceeds certain thresholds. In 2026, that surcharge begins at about $109,000 for single filers and $218,000 for joint filers, rising through five tiers with monthly extras from about $81 to over $600 depending on income. For 2027, the exact brackets arrive with the November announcement, and estimates put the entry threshold near $112,000 to $113,000 for singles.

The AEP consequence is that "premium" comparisons can mislead if they ignore IRMAA. A higher-income beneficiary who chooses a $40-per-month Part D plan may actually pay $40 plus an IRMAA surcharge that is identical no matter which plan they pick — so drug plan choice should be made on the plan's own costs, while the IRMAA surcharge is a separate, plan-independent number. If your 2025 income was inflated by a one-time event — selling a home, cashing out a retirement account, a final big year of work — you can file Form SSA-44 during the AEP to request a lower tier, and the sooner you do, the earlier your correct premium takes effect in January.

Medicare Open Enrollment for Existing vs. New Beneficiaries

The AEP means different things depending on where you are in your Medicare life. For existing beneficiaries — the majority — the window is a stable annual review: read the Annual Notice of Change, re-check your drugs and doctors against 2027 formularies and networks, compare on the Plan Finder, and change only when your data changes. For beneficiaries in their first year, the AEP is the first chance to correct what early enrollment decisions may have missed, like moving from a plan chosen at random into one chosen for your actual prescriptions. It is also the first year where a wrong choice that started January 1 of the current year can be undone for January 1 of the next.

For people who have not yet enrolled, the AEP is not your window — the Initial Enrollment Period around your 65th birthday is — but October and November are an ideal time to start learning before your own window opens, because the real 2027 numbers get published while you watch. One timing pattern matters at every stage: retire roughly in late fall of any year and your employer coverage end-date can land awkwardly relative to a January 1 plan start, so if you plan to retire in late 2026 or in 2027 with Medicare beginning at the same time, line up your SEP and your retirement date before you make either commitment. The AEP rewards the prepared in every case — early comparisons, verified numbers in November, and a deliberate decision by December 7.

What to Do After You Enroll: The January Checklist

Your choice by December 7 starts January 1, 2027, and a short checklist turns a smooth decision into a smooth year. Check that your Medicare card or plan ID reflects the plan you chose, and keep the enrollment confirmation in a safe place with your other Medicare documents. During January, review your first Explanation of Benefits or plan ID card against the drug list you were promised — if a medication you were told was covered is not listed, the plan's appeal and formulary exceptions process is your remedy, and it starts with a call to the plan. If you enrolled in a Part D plan, use the online pharmacy calculator to confirm your actual bottle-by-bottle costs match your estimate.

Finally, set aside the annual folders you now know you will need next August: the Annual Notice of Change that arrives at the end of September 2027 will require the same comparison, and having last year's decision and drug list on hand makes it a twenty-minute task instead of a week of anxiety. Medicare open enrollment is, at bottom, a calendar habit — the same two months, the same three documents (premium, formulary, network), the same December 7 deadline. Do it well once, keep the records, and every following year gets cheaper in effort even as the premiums do their slow climb.

Verified Official Sources

• Source: Medicare.gov — Open Enrollment
• Source: CMS — Medicare Open Enrollment
• Source: The Big 65 — Medicare Enrollment Periods

Frequently Asked Questions

When is Medicare open enrollment 2026-27?

October 15 to December 7, 2026. Changes take effect January 1, 2027.

What can I change during the AEP?

Switch Medicare Advantage plans, change or join Part D, or move between Original Medicare and a Medicare Advantage plan.

What is the MA Open Enrollment Period?

January 1 to March 31, 2027, for people already in Medicare Advantage who want a one-time switch to another MA plan or back to Original Medicare.

What if I miss the December 7 deadline?

Your coverage generally continues into 2027, unless you qualify for a special enrollment period or the MA Open Enrollment window.

Do I need to re-enroll every year?

No, coverage continues automatically. But review your plan each fall because costs and benefits change.

What is the deadline for Medicare open enrollment 2026?

December 7, 2026. The Annual Enrollment Period runs from October 15 to December 7, and your choices take effect January 1, 2027.

What can I change during the AEP?

You can switch between Original Medicare and Medicare Advantage, change Medicare Advantage plans, and join, drop or switch a Part D drug plan.

What is the Part D out-of-pocket cap for 2027?

It rises to $2,400 for 2027, up from $2,100 in 2026. Once your true out-of-pocket drug spending reaches that amount, covered drugs are free for the rest of the year.

Can I switch plans after December 7?

In most cases you need a Special Enrollment Period for a qualifying life event, or, if you are in Medicare Advantage, the January-March Medigap change window.

How do I know if my plan is changing its drug coverage?

Every plan mails an Annual Notice of Change by the end of September describing premium, drug tier and coverage changes that start January 1, 2027.

What is the difference between the AEP and the Medicare Advantage Open Enrollment Period?

The AEP (Oct 15-Dec 7) allows the full menu of changes; the January-March window only lets Medicare Advantage members switch plans or return to Original Medicare once.