What is the Medicare Annual Enrollment Period (AEP)?
The Annual Enrollment Period (AEP) runs October 15 through December 7 every year. It's the once-a-year window where anyone with Medicare can switch Medicare Advantage or Part D drug plans, drop a Medicare Advantage plan and return to Original Medicare, or pick up Part D for the first time. Choices made during AEP take effect January 1. AEP is NOT when you first sign up for Medicare — that's the Initial Enrollment Period around your 65th birthday or a Special Enrollment Period if you had qualifying employer coverage.
Dr. Ed Weir, PhD · 20 years inside Social Security · "Former" Sergeant, USMC
Updated April 2026
What is the Medicare Annual Enrollment Period (AEP)?
AEP is October 15–December 7 each year. During AEP, you can: (1) switch from one Medicare Advantage plan to another; (2) switch from MA back to Original Medicare; (3) switch from Original Medicare to MA; (4) switch from one Part D plan to another; (5) join Part D for the first time (LEP may apply if you're late). New coverage starts January 1. Read your Annual Notice of Change (ANOC) — it arrives by Sept 30 and tells you what's changing in your current plan. AEP is not the only window: the MA Open Enrollment Period (Jan 1–Mar 31) lets you switch MA plans once.
This whole page is about the Medicare Annual Enrollment Period
Free help from licensed Medicare advisors
AEP is the busiest — and most aggressively marketed — window in Medicare. Chapter Medicare's licensed advisors give you a free, side-by-side comparison without the high-pressure sales pitch. Tell them Dr. Ed sent you.
Here's how to walk into AEP without getting steamrolled.
Approaching AEP — or already in it? Here's the order I'd take.
1. Find your Annual Notice of Change (ANOC) before you do anything else
If you're already in a Medicare Advantage or Part D plan, your plan must mail an ANOC to you by September 30. The ANOC lays out exactly what's changing for the next plan year: premium, copays, drug formulary, network providers. Read it. Most of what people 'discover' during AEP about their plan was actually disclosed in the ANOC.
Medicare ANOC explanation ›2. Use the official Medicare Plan Finder
Medicare.gov's Plan Finder is the official tool. It compares Original Medicare vs. Medicare Advantage and Part D drug plans available in your ZIP code, and it can include your specific medications and pharmacy preferences. It's free, neutral, and doesn't try to sell you anything. Use it before you let anyone else's tool drive your decision.
Medicare Plan Finder ›3. Get free, unbiased help from SHIP or Chapter
State Health Insurance Assistance Program (SHIP) counselors are federally funded, free, and don't sell plans. Chapter Medicare's licensed advisors are also free and walk through Plan Finder with you side-by-side. Either is a far better starting point than a TV-ad lead form.
Find your local SHIP ›4. Don't take cold calls about Medicare Advantage or Part D
If your phone rings out of the blue and a stranger wants to discuss your Medicare — hang up. Cold-call solicitation about Medicare Advantage and Part D plans is prohibited under CMS's Medicare Communications and Marketing Guidelines (MCMG). Same with unsolicited texts and door-to-door visits. Real help is the people you call: SSA at 1-800-772-1213, Medicare at 1-800-633-4227, SHIP at , or Chapter at (352) 841-0632.
CMS Medicare Marketing Guidelines ›AEP 2026 by the numbers
Which of these fits your situation?
AEP looks the same to everyone in the ads but plays out differently depending on what you have now. Pick what fits.
I like my current plan — do I have to do anything?No — but read your ANOC anyway
If you don't make a change during AEP, you stay enrolled in your current Medicare Advantage or Part D plan. The plan automatically continues. But your current plan IS changing in some way for the next year — the ANOC tells you exactly how. Premium changes, copay changes, drug formulary changes, and network changes all happen January 1. A plan that worked great this year might not be the best fit next year. Read the ANOC before you decide to do nothing.
The ANOC is the single most important AEP document and the most ignored. Plans count on people not reading it. The ANOC arrives by Sept 30 — if you can't find yours, log into your plan's member portal or call them.
I'm on Original Medicare and thinking about switching to MAIt's a real decision — not a trivial one
AEP is one of the windows where you can switch from Original Medicare to a Medicare Advantage plan. Both work, but they work differently — networks, prior authorization, out-of-pocket caps, and Medigap rules all change. Crucially, if you've been on Original Medicare with Medigap and you switch to MA, getting back to a Medigap policy later (after Medigap open enrollment) is harder and may require medical underwriting. This is not a switch to make under sales pressure.
I'm not telling you to pick Original Medicare or Medicare Advantage — I'm telling you to make the decision with someone who isn't paid by either side. SHIP () and Chapter Medicare are good free starting points.
I'm on Medicare Advantage and thinking about going back to OriginalAEP lets you do this — but Medigap may be the catch
AEP allows you to drop a Medicare Advantage plan and return to Original Medicare effective January 1. The same window also lets you join a stand-alone Part D drug plan. The catch is Medigap: outside of your initial 6-month Medigap open enrollment at 65, Medigap insurers in most states can use medical underwriting and turn you down. Some states (e.g., NY, CT, MA, ME, with rules in CA and OR) have stronger guaranteed-issue protections. Check yours before you switch.
If you're considering moving from MA back to Original Medicare and you also want a Medigap policy, work out the Medigap piece BEFORE you drop the MA plan. SHIP and Chapter Medicare can map your state's specific rules.
My Part D drug costs spiked — should I switch?Use Plan Finder with your actual prescriptions
AEP is the right time to compare Part D plans. Medicare.gov's Plan Finder lets you enter your specific medications and preferred pharmacy and shows total annual cost for each plan available in your ZIP. The 2025 Inflation Reduction Act changes capped Part D out-of-pocket costs at $2,000 (rising to $2,100 in 2026), but plan-by-plan costs still vary widely. Don't pick on premium alone — the formulary tier of your specific drugs is usually what drives total cost.
The lowest-premium Part D plan is rarely the cheapest plan over the year if your drugs aren't on its preferred formulary. Always run your specific drug list through Plan Finder.
I'm on a tight income — are there programs that lower my AEP options' costs?Yes — Extra Help and MSP both apply
If your income is under 150% of the federal poverty level, the Low-Income Subsidy (Extra Help) lowers your Part D premium, deductible, and copays — and waives the Part D LEP. The Medicare Savings Program (MSP) can pay your Part B premium and (for QMB) other Medicare cost-sharing. Both are means-tested but a lot of moderate-income retirees qualify since the IRA expansion. Apply through SSA (Extra Help) and your state Medicaid office (MSP).
Extra Help and MSP are the most under-applied-for cost-assistance programs I encountered at SSA. People hear 'low-income' and assume they don't qualify. The 150% FPL line is higher than most people think.
I missed AEP — can I still switch?Maybe — there are several smaller windows
The MA Open Enrollment Period (Jan 1–Mar 31) lets people on Medicare Advantage make ONE change: switch to a different MA plan, or switch to Original Medicare with optional Part D. The 5-Star Special Enrollment Period (Dec 8–Nov 30) lets you switch into a 5-star Medicare Advantage or Part D plan available in your area, once per year. Other Special Enrollment Periods open if you move, lose Medicaid, or experience certain life events.
I'm helping my parent navigate AEPLead with their ANOC — not with a sales pitch
If you're helping a parent, partner, or relative through AEP, the most useful first step is finding their ANOC. Then ask whether anything about their health changed in the last year — new diagnoses, new prescriptions, new doctors. Then walk through Medicare.gov's Plan Finder with their actual drug list and preferred pharmacy. Then — and only then — talk to a SHIP counselor or Chapter advisor for an unbiased read. Don't lead with what your favorite advisor recommends.
My situation is different from any of theseTell me what's going on — we'll figure it out together
AEP situations get specific fast — chronic conditions that need certain specialists, expensive medications that may or may not be on a formulary, second homes in different states. SHIP counselors are trained for this and don't try to sell you anything. Reach them at or via shiphelp.org. Or use the chat below to describe your situation and I'll point you to the next right step.
Programs that interact with your AEP decisions.
Some programs change what's worth choosing during AEP. A few worth checking.
Medicare Enrollment Periods
AEP is one of five Medicare enrollment windows. Each does something different — confusing AEP with the IEP is the most expensive Medicare mistake.
Medicare Late Enrollment Penalty
AEP is the catch-up window for first-time Part D enrollees. The Part D LEP applies if you're enrolling more than 63 days after first becoming eligible.
Medicare Extra Help (LIS)
If your income is under 150% FPL, Extra Help lowers Part D premiums, deductibles, and copays — changing which AEP options make sense.
Medicare Savings Program (MSP)
QMB, SLMB, and QI may pay your Part B premium and other Medicare costs — changing what's worth choosing during AEP.
IRMAA (high-income surcharge)
If your income is over $109K single / $218K joint (2026), IRMAA stacks on top of Part B and Part D premiums. AEP plan choices interact with IRMAA — your Part D plan choice affects your IRMAA Part D bracket.
Medicare Prescription Drug Costs
The 2026 Part D out-of-pocket cap is $2,100 per IRA changes. Coverage gap (donut hole) is gone. Plan choice still affects your annual total cost a lot.
AEP questions I get most often
What can I actually change during AEP?
Five things: (1) switch from one Medicare Advantage plan to another; (2) drop MA and return to Original Medicare; (3) join MA from Original Medicare; (4) switch from one Part D plan to another; (5) join Part D for the first time (Part D LEP may apply if you're late). What you CAN'T do during AEP: drop Original Medicare, drop Part A, drop Part B, or get a new Medigap policy without underwriting (Medigap has its own rules separate from AEP).
Is AEP when I first sign up for Medicare?
No — that's a common mix-up. Your first chance to enroll in Medicare is your Initial Enrollment Period (IEP), the 7-month window around your 65th birthday (or via SSDI rules if you're under 65). AEP is for people already on Medicare who want to switch their MA or Part D plans for the next year. Confusing AEP with IEP is one of the most common reasons people end up with a Part B late-enrollment penalty.
Do I have to do anything during AEP if I'm happy with my plan?
No — if you don't make a change, you stay enrolled. But you should still read the Annual Notice of Change (ANOC) your plan mailed by Sept 30. The ANOC tells you exactly what's changing for the next year: premium, copays, drug formulary, network. Plans count on people not reading the ANOC. A plan that worked in 2026 might not be the right fit for 2027.
When does my new plan start if I switch during AEP?
January 1 of the following year. If you make a change between October 15 and December 7, the new coverage takes effect on January 1. If you make multiple changes during AEP, the last change you make is the one that takes effect.
Is the Medicare Advantage Open Enrollment Period (MA OEP) the same as AEP?
No — they're different windows. AEP runs Oct 15–Dec 7 and is open to everyone with Medicare. MA OEP runs Jan 1–Mar 31 and is only for people already enrolled in a Medicare Advantage plan. MA OEP allows ONE change: switch to a different MA plan, or switch back to Original Medicare with a stand-alone Part D plan. You can't use MA OEP to switch from Original Medicare to MA.
What's the 5-Star SEP and how is it different from AEP?
The 5-Star Special Enrollment Period runs December 8 through November 30 each year and lets you switch into a 5-star Medicare Advantage or Part D plan available in your area, once per year, outside of AEP. CMS publishes star ratings every fall. The 5-Star SEP is a way to upgrade if a 5-star plan becomes available where you live, but you can only use it once and only into a plan that has a 5-star rating.
Should I trust the calls and ads I get during AEP season?
Be careful. Cold-call solicitation about Medicare Advantage and Part D plans is prohibited under CMS's Medicare Communications and Marketing Guidelines (MCMG). If a stranger calls or texts you about Medicare without your permission, that's a violation. Some TV ads and mailers are legitimate but lead-generation-heavy — they're designed to capture you for a sales call, not to give you neutral information. The free, neutral options are Medicare.gov's Plan Finder, your state SHIP, and Chapter Medicare.
How do I compare Part D plans during AEP?
Use the Medicare.gov Plan Finder. Enter your specific medications, your preferred pharmacy, and your ZIP code. The tool ranks all Part D plans available to you by total annual cost (premium + deductible + copays for your drugs). Don't pick on premium alone — the formulary tier of YOUR specific drugs is usually what drives total cost. SHIP counselors and Chapter advisors will run Plan Finder with you for free.
Should I switch from Original Medicare to Medicare Advantage during AEP?
That's a personal decision and depends on your health needs, providers, drugs, and budget. AEP is the right window if you're going to do it. But understand the tradeoff: Original Medicare with Medigap and Part D gives you broad provider access nationwide and predictable costs. Medicare Advantage often costs less in premiums and may include extras (dental, vision, hearing, gym memberships) but uses networks, prior authorizations, and yearly out-of-pocket caps that can run into thousands. If you switch from Original to MA and later want to come back, Medigap may require medical underwriting in most states.
What if I miss AEP entirely?
If you're already on a Medicare Advantage plan, the MA Open Enrollment Period (Jan 1–Mar 31) gives you one more chance to make ONE change. The 5-Star SEP runs all year (Dec 8–Nov 30) for switching into a 5-star plan. Other Special Enrollment Periods open for specific life events: moving outside your plan's service area, losing Medicaid, qualifying for Extra Help, leaving an institution. None of these is as broad as AEP — mark your calendar.
Sources
Every figure and rule on this page is verified against primary sources. Last verified 2026-04-27.
- The Medicare Annual Enrollment Period (AEP) runs October 15 through December 7 each year, and changes take effect January 1. —medicare.gov(verified 2026-04-28)
- During AEP, beneficiaries may switch from one Medicare Advantage plan to another, drop MA and return to Original Medicare, switch from Original Medicare to MA, switch Part D plans, or join Part D for … —medicare.gov(verified 2026-04-28)
- Medicare Advantage and Part D plans are required to mail an Annual Notice of Change (ANOC) to enrollees by September 30 each year, detailing changes to premium, cost-sharing, drug formulary, and … —medicare.gov(verified 2026-04-28)
- The Medicare Advantage Open Enrollment Period (MA OEP) runs January 1 through March 31 each year and allows beneficiaries already in a Medicare Advantage plan to make one change: switch to another MA … —medicare.gov(verified 2026-04-28)
- The 5-Star Special Enrollment Period runs December 8 through November 30 each year and allows a beneficiary to switch into a 5-star Medicare Advantage or Part D plan available in their service area, … —medicare.gov(verified 2026-04-28)
- Cold-call solicitation about Medicare Advantage and Part D plans is prohibited under the CMS Medicare Communications and Marketing Guidelines (MCMG). —cms.gov(verified 2026-04-28)
- Medicare.gov's Plan Finder is the official CMS tool for comparing Medicare Advantage and Part D plans by ZIP code, including drug-specific cost calculations. —medicare.gov(verified 2026-04-28)
- Medicare Advantage members switching back to Original Medicare may face Medigap medical underwriting in most states because guaranteed-issue Medigap rights are limited outside specific Medigap open … —medicare.gov(verified 2026-04-28)
- The Inflation Reduction Act capped Part D out-of-pocket drug spending at $2,000 in 2025; the cap rises annually with the Part D growth rate. —cms.gov(verified 2026-04-28)
- The Initial Enrollment Period (IEP) for Medicare is the 7-month window including the 3 months before, the month of, and the 3 months after the beneficiary's 65th birthday. —medicare.gov(verified 2026-04-28)
- CMS publishes Medicare Advantage and Part D Star Ratings every fall to help beneficiaries compare plan quality. —cms.gov(verified 2026-04-28)
- The Medicare Beneficiary Identifier (MBI) and Social Security Number should never be given out in response to unsolicited calls; CMS does not initiate calls to ask for these identifiers. —medicare.gov(verified 2026-04-28)
- Beneficiaries who lose Medicaid eligibility have a Special Enrollment Period to enroll in or switch a Medicare Advantage or Part D plan, available outside AEP. —medicare.gov(verified 2026-04-28)
- Beneficiaries moving outside their Medicare Advantage or Part D plan's service area have a Special Enrollment Period to switch plans, generally lasting up to two months. —medicare.gov(verified 2026-04-28)
- Plans must include all six protected drug classes (anticonvulsants, antidepressants, antineoplastics, antipsychotics, antiretrovirals, and immunosuppressants) on their Part D formularies. —cms.gov(verified 2026-04-28)
- 1-800-MEDICARE (1-800-633-4227) is the official CMS phone number for Medicare beneficiaries to report fraud, ask plan questions, or update enrollment. —medicare.gov(verified 2026-04-28)
- State Health Insurance Assistance Programs (SHIPs) provide free, unbiased Medicare counseling and are funded through the federal Administration for Community Living. —law.cornell.edu(verified 2026-04-28)
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