When Is Medicare Open Enrollment? The State-by-State Calendar

🔑 10 Key Takeaways You Need Right Now

Medicare Open Enrollment runs October 15 through December 7 every year — changes you make during this window take effect January 1 of the following year. This is the primary annual window for switching plans.

There are actually six distinct Medicare enrollment periods, not three — the Initial Enrollment Period, General Enrollment Period, Annual Election Period (Open Enrollment), Medicare Advantage Open Enrollment Period, Medigap Open Enrollment Period, and Special Enrollment Periods all serve different purposes.

If you do nothing during Open Enrollment, your current plan automatically renews — but your costs, drug formulary, provider network, and benefits may have changed significantly. Doing nothing isn’t always harmless.

Your Initial Enrollment Period is a 7-month window around your 65th birthday — it starts 3 months before your birth month, includes the month itself, and ends 3 months after. Signing up in those first 3 months prevents coverage gaps.

Missing your Initial Enrollment Period triggers permanent penalties — a 10% Part B premium surcharge for every 12 months you delayed, plus a 1% Part D penalty per month without creditable drug coverage. These penalties last for life.

Medicare Advantage enrollees get an extra window from January 1 to March 31 — during the Medicare Advantage Open Enrollment Period, you can switch to a different MA plan or return to Original Medicare (one change only).

Medigap enrollment is not part of the annual Open Enrollment Period — your best (and often only) guaranteed-issue window for Medigap is the 6-month period starting when your Part B coverage begins. Only 21 states offer any annual Medigap enrollment protections.

Special Enrollment Periods are triggered by qualifying life events — moving, losing employer coverage, gaining Medicaid, marriage, or divorce can all unlock a 2-month window to change plans outside regular enrollment.

A new Special Enrollment Period exists in 2026 for incorrect provider directories — if you enrolled in a Medicare Advantage plan based on wrong network information from the Medicare Plan Finder tool, you can switch plans.

Every state has a free SHIP counselor who can help you one-on-one — the State Health Insurance Assistance Program provides unbiased, no-cost Medicare counseling and is available by calling 877-839-2675 to find your local office.

📅 The 6 Medicare Enrollment Periods Explained: Your Complete 2026 Calendar

The biggest confusion around Medicare enrollment is that people think there’s just one window. In reality, the federal government has built six separate enrollment mechanisms, each with different rules, different eligible populations, and different consequences. Here’s the full picture.

📅 Enrollment Period	Dates	Who It’s For	What You Can Do	When Coverage Starts
🟢 Initial Enrollment Period (IEP)	7 months around your 65th birthday	First-time enrollees turning 65	Enroll in Parts A, B, C, D, and Medigap	Depends on when you enroll during the window
🟡 General Enrollment Period (GEP)	January 1 – March 31	People who missed their IEP	Sign up for Part A and/or Part B only	July 1 of that year
🔵 Annual Election Period / Open Enrollment (AEP)	October 15 – December 7	All Medicare beneficiaries	Switch MA plans, join/drop Part D, move between Original Medicare and MA	January 1 of the following year
🟣 Medicare Advantage Open Enrollment (MA OEP)	January 1 – March 31	Current MA enrollees only	Switch MA plans or return to Original Medicare (one change only)	First of the month after enrollment
🟠 Medigap Open Enrollment	6 months from Part B effective date	New Part B enrollees	Buy any Medigap plan without medical underwriting	When Medigap policy is issued
🔴 Special Enrollment Periods (SEPs)	Varies by qualifying event	People with qualifying life events	Join/switch plans based on specific circumstances	Typically first of the month after enrollment

One critical detail most articles miss: the 5-Star Special Enrollment Period runs from December 8 through November 30 of the following year, allowing beneficiaries to switch once to a Medicare Advantage or Part D plan that CMS has rated 5 stars — but only if such a plan is available in your area.

🚨 What Actually Happens If You Do Nothing During Open Enrollment

This is the question that causes the most anxiety — and the answer depends entirely on your situation. If you’re already enrolled in a Medicare Advantage or Part D plan and do nothing during the October 15 – December 7 window, your current plan automatically rolls over into the next year. You won’t lose coverage.

But “automatically renewing” doesn’t mean “nothing changes.” Here’s what can shift without your approval between plan years:

⚠️ What Can Change Without Your Action	Impact
💊 Drug formulary changes	Medications you take may no longer be covered or may move to a higher-cost tier
🏥 Provider network changes	Your doctor, specialist, or preferred hospital may leave the network
💰 Premium increases	Your monthly cost could rise, sometimes significantly
📋 Prior authorization requirements	Procedures that were previously approved automatically may now require advance permission
🔄 Copay/coinsurance changes	Your cost-sharing amounts for visits, procedures, and drugs may increase
❌ Plan discontinuation	Your plan may be eliminated entirely — if so, you must actively choose a new one or you’ll be auto-enrolled

The Annual Notice of Change (ANOC) document your plan sends you each September is the single most important piece of mail you’ll receive all year. It outlines exactly what’s changing for the upcoming plan year. If you throw it away without reading it, you’re flying blind.

For beneficiaries on Original Medicare with no Advantage or Part D plan, the Open Enrollment Period is irrelevant unless you want to add coverage. Your Parts A and B continue unchanged.

🎂 The Initial Enrollment Period Is Your Single Most Powerful Medicare Window

If you’re approaching 65, your IEP is the enrollment period that matters most — and the one where mistakes are most expensive. This 7-month window is structured around your birth month.

🎂 If Your 65th Birthday Is In…	IEP Starts	IEP Ends	Best Time to Enroll
March 2026	December 2025	June 2026	December 2025 – February 2026 (before birth month)
June 2026	March 2026	September 2026	March 2026 – May 2026
September 2026	June 2026	December 2026	June 2026 – August 2026
December 2026	September 2026	March 2027	September 2026 – November 2026

Why does enrolling in those first 3 months matter so much? Coverage start dates depend on when during your IEP you sign up. Enroll in the 3 months before your birthday month, and coverage can begin as early as the first day of your birth month. Wait until your birth month or later, and you’ll face a 1–3 month delay before coverage kicks in — leaving you potentially uninsured.

If you’re still working at 65 and covered by an employer group health plan (through your own job or your spouse’s employer with 20+ employees), you can delay Medicare Part B enrollment without penalty. Once that employer coverage ends, you’ll have an 8-month Special Enrollment Period to sign up for Part B. But be careful: COBRA coverage and retiree health plans do not count as “employer group coverage” for this purpose. Delaying Part B while on COBRA will result in penalties.

💸 The Penalty Math That Could Cost You Thousands Over a Lifetime

Late enrollment penalties are Medicare’s way of discouraging people from gaming the system by waiting until they’re sick to sign up. But these penalties aren’t a one-time fee — they’re permanent surcharges that compound over decades.

❌ Penalty Type	How It’s Calculated	Duration	Example
🅱️ Part B late enrollment penalty	10% premium increase for each full 12-month period you delayed	Permanent — for as long as you have Part B	Delayed 3 years = 30% surcharge. Instead of $202.90/month, you’d pay $263.77/month for life
💊 Part D late enrollment penalty	1% of national base beneficiary premium ($38.99 in 2026) × months without creditable coverage	Permanent — for as long as you have Part D	24 months without coverage = ~$9.36/month added to your Part D premium permanently

The Part B penalty alone, compounded over a 20-year retirement, can cost tens of thousands of dollars. A 3-year delay translates to roughly $730 extra per year, or over $14,600 over 20 years — and that’s before accounting for annual premium increases.

🏥 The Medigap Enrollment Trap Most Retirees Don’t See Coming

Here’s a fact that catches an alarming number of new Medicare beneficiaries off guard: the annual Open Enrollment Period (October 15 – December 7) does not apply to Medigap plans. You can always apply for Medigap at any time, but insurers can reject you, charge higher premiums, or impose waiting periods for pre-existing conditions outside your guaranteed-issue window.

Your Medigap Open Enrollment Period is a one-time, 6-month window that starts the month your Part B coverage begins. During this period, insurance companies must sell you any Medigap policy they offer, at the best available price, regardless of your health history. Once this window closes, your protections evaporate in most states.

However, 21 states now offer at least some annual guaranteed-issue access to Medigap, though the specifics vary:

🗺️ State Medigap Protections (2026)	Level of Protection
🟢 Connecticut, Massachusetts, Maine, New York, Vermont	Year-round or continuous guaranteed-issue enrollment for all or most Medigap plans
🟡 California, Illinois, Missouri, Oregon, Washington + others	Annual birthday-rule windows or limited guaranteed-issue switching rights
🔴 Remaining states	No annual Medigap enrollment protections beyond the initial 6-month window

In California, for example, the “birthday rule” allows Medigap enrollees to switch to a new plan with equal or lesser benefits within 30 days of their birthday each year, without medical underwriting. Missouri, Illinois, Oregon, and several others have similar provisions. If you live in a state without these protections, your initial 6-month Medigap enrollment window is essentially your only realistic chance to secure comprehensive supplemental coverage.

📞 Special Enrollment Periods: The Hidden Doors Most People Don’t Know Exist

Special Enrollment Periods are available year-round, but only if specific qualifying life events trigger them. Most SEPs last 2 months, and you’ll typically need documentation to prove eligibility.

🔑 Qualifying Life Event	SEP Duration	What You Can Change
🏠 You move to a new area outside your plan’s service zone	2 months	Switch MA or Part D plans
💼 You lose employer/union coverage	8 months for Part B; 2 months for MA/Part D	Enroll in Part B, join MA or Part D plan
🏥 You enter or leave a skilled nursing facility	While in the facility + 2 months	Switch or join MA/Part D plans
💚 You gain or lose Medicaid/Extra Help eligibility	Once per calendar month	Join, switch, or drop MA/Part D
💍 Marriage, divorce, or death of spouse affecting coverage	2 months	Join/switch plans
⭐ A 5-star rated plan is available in your area	December 8 – November 30 (once annually)	Switch to the 5-star plan
🆕 2026 only: incorrect Medicare Plan Finder provider directory	Case-by-case	Switch from incorrectly marketed MA plan

The dual-eligible SEP (for people with both Medicare and full Medicaid) is one of the most powerful but least-known provisions. It allows plan changes once every calendar month, giving dual-eligible beneficiaries continuous flexibility that other enrollees don’t have.

📞 Your State-by-State Free Medicare Counseling Directory

Every state operates a State Health Insurance Assistance Program (SHIP) that provides free, unbiased, one-on-one Medicare counseling. These counselors are not affiliated with any insurance company and do not sell plans. They’re funded by federal grants and exist solely to help beneficiaries make informed decisions.

The national SHIP hotline is 877-839-2675, and the main Medicare service line is 1-800-633-4227 (1-800-MEDICARE), available 24/7.

🗺️ State	📞 SHIP Program Name & Toll-Free Number
🏷️ Alabama	SHIP — 1-800-243-5463 (AgeLine)
🏷️ Alaska	SHIP — 1-800-478-6065
🏷️ Arizona	SHIP — 1-800-432-4040
🏷️ Arkansas	SHIIP — 1-800-224-6330
🏷️ California	HICAP — 1-800-434-0222
🏷️ Colorado	SHIP — 1-888-696-7213
🏷️ Connecticut	CHOICES — 1-800-994-9422
🏷️ Delaware	ELDERinfo — 1-800-336-9500
🏷️ District of Columbia	HICP — (202) 739-0668
🏷️ Florida	SHINE — 1-800-963-5337
🏷️ Georgia	GeorgiaCares — 1-800-669-8387
🏷️ Hawaii	Sage PLUS — 1-888-875-9229
🏷️ Idaho	SHIBA — 1-800-247-4422
🏷️ Illinois	SHIP — 1-800-548-9034
🏷️ Indiana	SHIP — 1-800-452-4800
🏷️ Iowa	SHIIP — 1-800-351-4664
🏷️ Kansas	SHICK — 1-800-860-5260
🏷️ Kentucky	SHIP — 1-877-293-7447
🏷️ Louisiana	SHIIP — 1-800-259-5301
🏷️ Maine	SHIP — 1-877-353-3771
🏷️ Maryland	SHIP — 1-800-243-3425
🏷️ Massachusetts	SHINE — 1-800-243-4636
🏷️ Michigan	MMAP — 1-800-803-7174
🏷️ Minnesota	Senior LinkAge Line — 1-800-333-2433
🏷️ Mississippi	MICAP — 1-800-948-3090
🏷️ Missouri	CLAIM — 1-800-390-3330
🏷️ Montana	SHIP — 1-800-551-3191
🏷️ Nebraska	SHIIP — 1-800-234-7119
🏷️ Nevada	SHIP — 1-800-307-4444
🏷️ New Hampshire	ServiceLink — 1-866-634-9412
🏷️ New Jersey	SHIP — 1-800-792-8820
🏷️ New Mexico	Benefits Counseling — 1-800-432-2080
🏷️ New York	HIICAP — 1-800-701-0501
🏷️ North Carolina	SHIIP — 1-800-443-9354
🏷️ North Dakota	SHIC — 1-888-575-6611
🏷️ Ohio	OSHIIP — 1-800-686-1578
🏷️ Oklahoma	SHIP — 1-800-763-2828
🏷️ Oregon	SHIBA — 1-800-722-4134
🏷️ Pennsylvania	APPRISE — 1-800-783-7067
🏷️ Rhode Island	SHIP — (401) 462-4444
🏷️ South Carolina	I-CARE — 1-800-868-9095
🏷️ South Dakota	SHIINE — 1-800-536-8197
🏷️ Tennessee	TN SHIP — 1-877-801-0044
🏷️ Texas	HICAP — 1-800-252-9240
🏷️ Utah	SHIP — 1-800-541-7735
🏷️ Vermont	SHIP — 1-800-642-5119
🏷️ Virginia	VICAP — 1-800-552-3402
🏷️ Washington	SHIBA HelpLine — 1-800-562-6900
🏷️ West Virginia	WV SHIP — 1-877-987-4463
🏷️ Wisconsin	SHIP — 1-800-242-1060
🏷️ Wyoming	WSHIIP — 1-800-856-4398

Insider tip: SHIP counselors are especially valuable during the October 15 – December 7 Open Enrollment window, which means their phone lines get extremely busy. Call early in October or early in the day to avoid long wait times. Many SHIPs also offer in-person appointments and virtual counseling sessions.

🔄 How to Enroll in Medicare for the First Time: The Step-by-Step Sequence

If you’re turning 65 and enrolling for the first time, the process depends on whether you’re already receiving Social Security benefits.

🔄 Your Situation	What Happens
✅ Already receiving Social Security or Railroad Retirement benefits	You’re automatically enrolled in Parts A and B. Your Medicare card arrives approximately 3 months before you turn 65. You can opt out of Part B if you wish.
❌ Not yet collecting Social Security	You must actively enroll. Apply online at ssa.gov, call Social Security at 1-800-772-1213, or visit your local Social Security office during your 7-month IEP.
💼 Still working with employer coverage	You can enroll in Part A (free) now and delay Part B without penalty. When employer coverage ends, use your 8-month SEP to add Part B.
♿ Under 65 with a disability	You’re enrolled automatically after receiving Social Security Disability Insurance (SSDI) for 24 months.

Once you have Parts A and B, you then choose your coverage path. You’ll need to decide between staying on Original Medicare (and potentially adding a Medigap policy plus a standalone Part D drug plan) or enrolling in a Medicare Advantage plan (which typically bundles everything).

This decision should ideally be made before your Part B effective date, because your 6-month Medigap Open Enrollment Period begins at that moment. If you think you might want Medigap but aren’t sure, enroll anyway during that window — you can always cancel, but you can rarely get the same guaranteed-issue terms again.

⚕️ Medicaid Open Enrollment vs. Medicare Open Enrollment: They’re Not the Same Thing

A common source of confusion: Medicaid enrollment operates on a completely different calendar than Medicare. Medicaid applications can be submitted year-round in every state — there is no “open enrollment period” for Medicaid. If you qualify based on income and (in some states) assets, you can apply at any time through your state Medicaid office.

⚕️ Medicare vs. Medicaid Enrollment	Medicare	Medicaid
📅 Open enrollment window	October 15 – December 7 annually	Year-round — apply anytime
👤 Eligibility basis	Age 65+ or disability	Income and resources (varies by state)
🏛️ Administered by	Federal government (CMS)	State Medicaid agencies
🔄 Can you have both?	Yes — called “dual eligible”	Yes — dual-eligible beneficiaries get extra protections
📞 Where to apply	ssa.gov or 1-800-772-1213	Your state Medicaid office or healthcare.gov

If you qualify for both Medicare and Medicaid (dual eligible), you unlock some of the most generous benefits in the entire system — including Medicare Savings Programs that can pay your Part B premium, plus Extra Help with drug costs. Dual-eligible beneficiaries also get the monthly SEP allowing plan changes every single month.

❓ Frequently Asked Questions

What is the best time to enroll in Medicare? The best time is during the first 3 months of your Initial Enrollment Period — the 3 months before the month you turn 65. This ensures your coverage starts on the first day of your birth month with no gap. If you wait until your birth month or later, coverage start dates are delayed by 1 to 3 months.

What happens if I miss Open Enrollment entirely? If you miss the October 15 – December 7 Annual Election Period, your current Medicare Advantage or Part D plan automatically renews with whatever changes the insurer has made for the new year. You cannot make changes until the next Open Enrollment unless you qualify for a Special Enrollment Period. If you’re in a Medicare Advantage plan, you also have the January 1 – March 31 MA OEP to make one change.

Is Medicare Open Enrollment the same in every state? The federal enrollment dates (IEP, GEP, AEP, MA OEP) are identical in all 50 states, Washington D.C., and U.S. territories. However, state-specific rules apply to Medigap enrollment, Medicare Savings Program eligibility, and which plans are available in your area. California, Connecticut, Maine, Massachusetts, Missouri, and New York, among others, have unique Medigap enrollment protections that vary from federal rules.

When is Medicare Open Enrollment in California? The same as every other state: October 15 through December 7. However, California has a special “birthday rule” for Medigap that allows existing Medigap policyholders to switch to a different Medigap plan with equal or lesser benefits within 30 days of their birthday each year, without medical underwriting. California’s SHIP program is called HICAP and can be reached at 1-800-434-0222.

Can I change my Medicare plan outside of Open Enrollment? Yes, but only if you qualify for a Special Enrollment Period triggered by a qualifying life event (such as moving, losing employer coverage, gaining or losing Medicaid, or being enrolled in a plan with a low star rating). Dual-eligible beneficiaries and those receiving Extra Help can change plans once per calendar month year-round.

Do I have to re-enroll in Medicare every year? No. Once you’re enrolled in Medicare, your coverage continues automatically. You only need to take action if you want to change plans, if your plan is being discontinued, or if your service area has changed. Review your Annual Notice of Change each September to confirm your current coverage still meets your needs.

What if I’m still working at 65 — should I enroll in Medicare? If your employer has 20 or more employees and you have group health coverage through that employer, you can delay Part B enrollment without penalty. You should still enroll in Part A (it’s free and doesn’t affect employer coverage or HSA contributions — though HSA contributions must stop once you enroll in any part of Medicare). When you stop working or lose employer coverage, use your 8-month Special Enrollment Period to enroll in Part B.

What’s the difference between the Annual Election Period and the MA Open Enrollment Period? The Annual Election Period (October 15 – December 7) is for all Medicare beneficiaries and allows multiple plan changes. The Medicare Advantage Open Enrollment Period (January 1 – March 31) is only for people already enrolled in an MA plan, allows just one change (switching MA plans or returning to Original Medicare), and takes effect the first of the following month rather than January 1.

Is there a penalty for not enrolling in a Medicare Part D drug plan? Yes. If you go 63 or more consecutive days without Part D or other creditable drug coverage after your Initial Enrollment Period ends, you’ll face a permanent late enrollment penalty. In 2026, the penalty equals 1% of the national base beneficiary premium ($38.99) multiplied by the number of months you went uncovered — and you’ll pay this surcharge for as long as you have Part D coverage.

Where can I get free help choosing a Medicare plan? Your state’s SHIP program provides free, unbiased counseling from trained volunteers who have no ties to any insurance company. Call the national SHIP locator at 877-839-2675, or call 1-800-MEDICARE (1-800-633-4227) 24 hours a day, 7 days a week. You can also use the Medicare Plan Finder tool at medicare.gov to compare plans, costs, and quality ratings side by side.