6-Month Medigap Open Enrollment Period

The 6-month Medigap open enrollment period is the best time to buy a Medicare Supplement plan: you can generally choose any policy sold in your state without medical underwriting or higher prices based on health conditions. The key is knowing exactly when this one-time window begins.

Your enrollment period starts the month you are both 65 or older and enrolled in Medicare Part B, then lasts for six months. Missing it does not mean you cannot buy Medigap later, but your choices, costs, and acceptance may depend on your health and state rules. Continue reading to discover what a Medigap plan is.

Key takeaways

  • Your one-time Medigap enrollment window starts when you are 65 or older and Part B begins.
  • The window lasts six full months, starting on the first day of your Part B effective month.
  • During this period, insurers generally cannot deny coverage, charge more, or delay enrollment because of health.
  • After the window, medical underwriting may affect eligibility and premiums unless you have guaranteed-issue rights.
  • Medigap works with Original Medicare, not Medicare Advantage, and usually requires separate Part D drug coverage.
  • Compare standardized plan letters, premiums, rating methods, discounts, and carrier service before applying.

Compare plans and enroll online

The 6-Month Medigap Open Enrollment Period, Explained

For many Medicare beneficiaries, the best time to buy a Medicare Supplement Insurance policy is also the easiest to miss. The 6-month Medigap open enrollment period is a one-time window that begins the first month you are both 65 or older and enrolled in Medicare Part B.

It lasts for six consecutive months, including the month Part B takes effect, not six months after you receive your Medicare card. During this period, insurers selling Medigap coverage in your state generally must offer you any policy they sell, regardless of preexisting conditions or past medical history. Key protections include:

  • Insurers cannot use medical underwriting to charge you more because of your health.
  • They cannot deny your application or delay coverage because of preexisting conditions.
  • You can choose from any Medigap policy the insurer sells in your state.

That protection can be especially valuable for older adults managing chronic conditions or anticipating higher out-of-pocket costs under Original Medicare.

Medigap policies work alongside Original Medicare, helping pay certain deductibles, coinsurance, and copayments that Parts A and B do not fully cover. They are not used with Medicare Advantage plans, and they typically do not include prescription drug coverage, so a separate Part D plan may be needed.

Once this enrollment period ends, applying for insurance can become more complicated. In many states, companies may review your health history, limit the plans available to you, or charge a higher premium.

Certain qualifying events can create guaranteed-issue rights later, but those protections are narrower than the initial open enrollment window. Comparing coverage options before Part B begins, and confirming when that effective date falls, gives you the widest choice and the strongest consumer protections. Continue reading our other articles on the topic, such as What Is the Most Comprehensive Medigap Plan?

Medigap enrollment timing checklist

  • Confirm your Medicare Part B effective date; your six-month Medigap window starts that same month.
  • Apply during the window for broad plan access without health-based denials, delays, or higher premiums.
  • Compare standardized Medigap plans and premiums before Part B begins to maximize your options.
  • Remember Medigap supplements Original Medicare, helping with eligible deductibles, copayments, and coinsurance.
  • Do not pair Medigap with Medicare Advantage; these coverage types generally cannot be used together.
  • Consider separate Part D coverage, since most Medigap policies do not include outpatient prescription drugs.
  • After open enrollment ends, later guaranteed-issue rights may exist but are typically more limited.

The 6-month Medigap open enrollment period

When the Medigap Open Enrollment Period Starts and Ends

Your medigap open enrollment period is a one-time six-month window tied to Medicare Part B, not to the date you choose a Medigap plan. The time that begins is the first day of the month your Part B coverage starts, provided you are 65 or older.

During this enrollment period, insurers generally cannot deny you a policy or charge more because of health conditions. Knowing how Medicare’s parts work together helps prevent a missed deadline.

Calculate Your Six-Month Window From Your Part B Effective Date

For most beneficiaries, the calculation is straightforward: find the effective date on your Medicare Part B card or confirmation notice, then count forward six full months. Your Medigap open enrollment period starts on the first day of that month, even if your Part B coverage takes effect later in the month.

For example, if Part B becomes effective July 1, your six-month window runs from July 1 through December 31. If it begins July 15, the window still starts July 1 and ends December 31. The key date is the month Part B takes effect, rather than the day you submit a Medigap application.

If you enrolled in Part B before turning 65, your Medigap rights do not usually begin until the first day of the month you are both age 65 and enrolled in Part B. Someone whose birthday is in October and who already has Part B, for instance, generally has a window beginning October 1.

This is an important distinction for beneficiaries comparing plans while moving from employer coverage or another arrangement. Applying early is allowed in many cases, but the protections attached to open enrollment depend on the official start date. Keep copies of your Medicare notice and confirm the effective date with the carrier before assuming a deadline applies.

Delayed Part B and Other Timing Details to Confirm

Medicare beneficiaries who delay Part B because they have qualifying employer group health coverage should pay especially close attention. Delaying Part B can also delay the start of Medigap enrollment: the six-month open enrollment period generally does not begin until Part B becomes effective and you are at least 65.

That can be useful for someone continuing to work past 65, but it is worth confirming that the employer coverage qualifies under Medicare’s rules before postponing Part B. Retiree coverage, COBRA, and some smaller employer arrangements may not provide the same protection from late-enrollment consequences. Those decisions can affect both Medicare timing and the transition to supplemental coverage.

  • Confirm when Part B will become effective.
  • Verify that the employer coverage qualifies under Medicare’s rules.
  • Check whether a special right applies before changing coverage.

Also distinguish Medigap open enrollment from Medicare’s annual fall enrollment period. The annual period may let you change Medicare Advantage or prescription drug coverage, but it does not recreate your federal Medigap guaranteed-issue window.

After the initial period ends, insurers in many states may use medical underwriting when you apply, potentially affecting price or eligibility. There are exceptions, including certain guaranteed-issue rights after losing qualifying coverage or leaving a Medicare Advantage plan in specific circumstances.

State rules may provide additional protections as well. Before changing coverage, verify your Part B effective date, the type of coverage you are leaving, and whether a special right applies to your situation.

Medicare timing checkpoints

  • Confirm your employer coverage qualifies before delaying Part B.
  • Remember Medigap open enrollment generally starts when Part B becomes effective.
  • Verify retiree coverage, COBRA, and small-employer plans do not create late-enrollment risks.
  • Do not confuse annual fall enrollment with your one-time federal Medigap enrollment window.
  • Check whether guaranteed-issue rights apply after losing coverage or leaving Medicare Advantage.
  • Review state Medigap protections, which may offer additional enrollment rights.
  • Document your Part B effective date before changing or ending coverage.

What You Can Do When You Buy Medigap During This Window

When you buy Medigap during your protected enrollment window, you can generally choose from available Medigap policies without answering health questions or having preexisting conditions affect approval.

That freedom makes this an important time to compare benefits, service, and premiums across carriers. The right Medigap policy should fit your budget today while providing dependable help with Medicare’s out-of-pocket costs over time.

How to Compare a Medigap Plan Before You Apply

Start with the lettered Medigap plan you want, not the company name. In most states, plans with the same letter provide the same standardized coverage, regardless of which insurer sells them.

For example, one Plan G covers the same Medicare-approved gaps as another Plan G; the meaningful differences are usually the premium, underwriting rules outside protected enrollment, customer experience, and how rates may change. Ask each carrier how it sets premiums.

A community rating generally charges the same base rate to everyone in an area, while issue-age rating is based on your age when you enroll. Attained-age rating may begin lower but can increase as you get older, in addition to changes tied to medical costs or inflation.

No rating method guarantees the lowest long-term cost, but knowing the method gives you a clearer basis for comparison. Then look beyond the first monthly premium. Confirm household discounts, payment fees, available service channels, and the carrier’s history of rate stability in your state.

Compare the exact same Medigap policies side by side, and make sure you understand what Medicare still requires you to pay, including Part B costs and, depending on the plan, the Part B deductible. A local licensed agent can help you review plans without confusing standardized coverage with insurer-specific pricing.

Medigap comparison checklist

  • Choose the Medigap letter first; same-letter plans generally provide identical standardized benefits within your state.
  • Compare premiums only for the exact same plan letter and benefit version.
  • Ask whether rates are community-rated, issue-age-rated, or attained-age-rated.
  • Review the insurer’s historical rate increases and rate stability in your state.
  • Confirm household discounts, payment options, billing fees, and available customer service channels.
  • Understand underwriting requirements if you apply outside a protected enrollment period.
  • Identify remaining Medicare costs, including Part B premiums and any applicable deductible.

Your Medigap Enrollment Timeline, From Preparation to Application

Medigap enrollment is less about waiting for a single national deadline and more about recognizing the window that applies to you. For most people, the key date is the start of Medicare Part B. Your six-month Medigap Open Enrollment Period begins the month you are both 65 or older and enrolled in Part B.

During that period, you can sign up for any Medigap policy sold in your state, and insurers generally cannot deny you coverage or charge more because of preexisting health conditions. Start preparing a few months before Part B takes effect. Confirm whether you will enroll in Part B automatically or need to apply through Social Security, especially if you are retiring after employer coverage.

Then compare standardized plan benefits, available carriers, household discounts, customer service records, and the premium structure, not simply the lowest first-year price. A policy with the same letter name offers the same core benefits within a state, but insurance companies can set different premiums and may price increases differently over time.

Once you have selected a plan, submit your application early enough for coverage to begin when you want it to. Many people choose a Medigap policy effective on the same day as Part B, helping limit gaps in out-of-pocket protection. Keep copies of your application, confirmation, and premium notices.

If you apply after your open enrollment period, you may face medical underwriting unless you qualify for a guaranteed-issue right, such as losing certain employer or Medicare Advantage coverage. Some states offer additional consumer protections or birthday rules, so local guidance can make a meaningful difference before you make a change.

Medigap enrollment timeline checklist

  • Confirm when Medicare Part B starts, since it triggers your primary Medigap enrollment window.
  • Prepare several months ahead, especially if retirement means leaving employer-sponsored health coverage.
  • Verify whether Part B enrollment is automatic or requires an application through Social Security.
  • Use your six-month Open Enrollment Period, beginning when you are 65 or older and enrolled in Part B.
  • Compare standardized benefits, carrier service, household discounts, premiums, and likely long-term rate increases.
  • Apply early enough to align Medigap coverage with your Part B effective date.
  • Save application records, coverage confirmations, and premium notices for future reference.
  • Check state-specific protections or guaranteed-issue rights before changing coverage after open enrollment.

Find & Compare Plans Online

Speak with a licensed insurance agent

1-877-436-2343TTY 711

Mon-Fri: 8am-9pm ET

Medigap Open Enrollment and Other Medicare Enrollment Dates

Medigap open enrollment is one of Medicare’s most valuable timing protections, but it is often confused with the annual Medicare enrollment season. The dates serve different purposes, and missing the distinction can affect both your plan choices and what you pay.

Your one-time Medigap Open Enrollment Period begins the month you are both 65 or older and enrolled in Medicare Part B. It lasts six months. During that window, insurers must generally sell you any Medigap policy available in your area, regardless of pre-existing conditions.

They cannot use medical underwriting to deny coverage or raise your premium because of your health history. For many people leaving employer coverage, the Part B effective date, not simply their 65th birthday, is the date that matters.

By contrast, Medicare’s Annual Enrollment Period runs from October 15 through December 7 each year. This is when people can change a Medicare Advantage plan, move between Medicare Advantage and Original Medicare, or adjust Part D prescription drug coverage for the following year.

It is commonly called open enrollment, but it does not create a new guaranteed Medigap right for everyone who wants to leave an Advantage plan. There is also the Medicare Advantage Open Enrollment Period, from January 1 through March 31.

If you are already enrolled in a Medicare Advantage plan, you may make one change: switch to another Advantage plan or return to Original Medicare, with or without Part D coverage. In most states, however, applying for Medigap after this change may involve medical underwriting unless you qualify for a guaranteed-issue right.

Special Enrollment Periods can apply after events such as moving out of a plan’s service area, losing employer coverage, or a plan ending its contract. State rules may provide additional Medigap protections, particularly for people under 65 who qualify for Medicare through disability. Before dropping a Medicare Advantage plan, confirm whether a Medigap insurer will accept your application and what coverage can begin when.

Medigap and Medicare Enrollment Periods at a Glance

Enrollment period When it occurs What it allows Medigap implication
Medigap Open Enrollment Begins the month you are both age 65 or older and enrolled in Medicare Part B; lasts six months Buy any Medigap policy available in your area Insurers generally must sell a policy regardless of pre-existing conditions and cannot use medical underwriting to deny coverage or increase premiums based on health history.
Medicare Annual Enrollment October 15 through December 7 each year Change Medicare Advantage plans, move between Medicare Advantage and Original Medicare, or adjust Part D coverage for the following year Does not create a new guaranteed Medigap right for everyone leaving a Medicare Advantage plan.
Medicare Advantage Open Enrollment January 1 through March 31 People already enrolled in Medicare Advantage may make one change: switch to another Advantage plan or return to Original Medicare, with or without Part D coverage In most states, a Medigap application after returning to Original Medicare may involve medical underwriting unless you qualify for a guaranteed-issue right.
Special Enrollment Periods After qualifying events, such as moving out of a plan’s service area, losing employer coverage, or a plan ending its contract Make Medicare coverage changes related to the qualifying event State rules may provide additional Medigap protections, including for some people under 65 who qualify for Medicare through disability.

After Medigap Open Enrollment: Underwriting and the Waiting Period

Once Medigap open enrollment has passed, the path to a Medigap plan may involve health questions, medical underwriting, and potentially higher premiums. Insurers can consider existing health conditions when you apply, and they may decline an application where state rules allow.

A waiting period for pre-existing conditions can also apply in limited circumstances, particularly when prior creditable coverage is absent. Still, certain events create protections that can make it easier to buy Medigap.

When Guaranteed Issue Rights May Still Let You Apply

Guaranteed issue rights are federal protections that require an insurer to sell you a qualifying Medigap policy without medical underwriting. In other words, the company generally cannot deny coverage, charge more because of health history, or impose a pre-existing-condition waiting period.

These rights are not available simply because you want to change plans; they arise when specific Medicare coverage ends or changes under qualifying circumstances. Common examples include losing a Medicare Advantage plan because it leaves your service area or stops serving Medicare beneficiaries, returning to Original Medicare after a qualifying trial right, or losing certain employer or union health coverage that supplements Medicare.

You may also have issue rights if a Medicare SELECT policy becomes unavailable after you move, or if an insurer misled you or failed to follow its contract. Timing matters. Many protections have a limited enrollment window, often beginning before coverage ends and lasting about 63 days afterward.

Keep notices showing the end date and reason for the loss of coverage; an insurance carrier may request them with your application. The Medigap policy choices available under guaranteed issue rules can be narrower than the full menu of plans, and state law may provide additional protections beyond the federal baseline.

After Medigap open enrollment: underwriting and the waiting period

State Rules and Life Changes That Can Affect Your Options

Medigap coverage is regulated at both the federal and state level, so the choices available to you may depend on where you live as well as when you apply. The core federal protections are important, but several states provide additional enrollment opportunities or stronger consumer protections than the national baseline.

That makes it worthwhile to review the rules that apply in your state before assuming you have missed your chance to buy or change a policy. A key protection is guaranteed issue rights.

These rights generally allow you to buy certain Medigap policies without medical underwriting after specific life changes, such as losing qualifying employer-sponsored retiree coverage, moving out of a Medicare Advantage plan’s service area, or when a Medicare Advantage plan leaves Medicare or stops serving your area.

When guaranteed issue rights apply, carriers cannot refuse your application, charge more because of pre-existing health conditions, or impose a waiting period for coverage of those conditions beyond what Medicare rules allow.

Timing matters. Many issue rights are available only for a limited window, often beginning shortly before your current coverage ends and continuing for a period afterward. Keep written notices showing why coverage ends, along with plan termination letters and proof of prior coverage.

Those documents can be essential when applying for Medigap coverage under a protected enrollment right. Outside of these windows, carriers in many states may use medical underwriting to decide whether to accept an application and what premium to offer.

State rules can change that picture: some states require broader access, offer annual switching periods, or limit how insurers consider health history. Because Medigap policies, premiums, and protections vary by location, confirm the current requirements through your State Health Insurance Assistance Program or state insurance department before making a change.

Common Questions About the 6-Month Medigap Open Enrollment Period

The 6-month Medigap open enrollment period is the clearest window to buy a Medicare Supplement policy: it begins the first month you are 65 or older and enrolled in Medicare Part B, then runs for six months. During this time, insurers generally must sell you any Medigap plan available in your area, regardless of pre-existing health conditions.

You can sign up for a policy later, but insurers may use medical underwriting, charge more, or decline your application unless you qualify for a guaranteed-issue right. This enrollment period is different from Medicare’s annual fall enrollment window.

That fall period is primarily for changing a Medicare Advantage plan or Part D drug coverage; it does not create a new federal right to buy Medigap without underwriting. You also cannot generally use a Medigap policy alongside a Medicare Advantage plan.

To enroll in Medigap, you would first need to return to Original Medicare, and the timing can matter greatly. Compare premiums, household discounts, rate histories, and how each insurer prices future increases, not just the monthly cost shown today.

Standardized Medigap benefits make it easier to compare plans with the same letter, although premiums and service vary by carrier. Before replacing existing coverage, confirm whether your current policy has benefits you would lose and whether a new policy will be approved.

Some states offer additional protections or enrollment opportunities, particularly for people under 65 who qualify for Medicare because of disability. A local Medicare adviser can help you check the rules where you live, coordinate effective dates, and avoid an unintended gap in coverage.

Compare plans and enroll online

Frequently asked questions

When does the Medigap open enrollment period begin?

Your six-month Medigap Open Enrollment Period begins on the first day of the month you are both age 65 or older and enrolled in Medicare Part B. It is based on your Part B effective month, not the day you receive your Medicare card or submit an application.

How long does Medigap open enrollment last?

The federal Medigap open enrollment period lasts for six consecutive months. For example, if Part B takes effect in July, your protected enrollment window generally runs from July 1 through December 31.

Can I buy Medigap if I have a preexisting condition?

During your initial six-month Medigap enrollment period, insurers generally cannot deny your application, charge a higher premium, or delay coverage because of your health history or preexisting conditions. Rules outside this period can differ by state and situation.

What happens if I miss my Medigap open enrollment period?

After the window ends, insurers in many states may use medical underwriting. They may consider your health when deciding whether to accept your application or what premium to charge. You may still have guaranteed-issue rights after certain qualifying coverage losses.

Is Medigap open enrollment the same as Medicare Annual Enrollment?

No. Medicare Annual Enrollment, held October 15 through December 7, is primarily for changing Medicare Advantage and Part D drug coverage. It does not usually provide a new federal right to buy Medigap without medical underwriting.

Can I have Medigap and Medicare Advantage at the same time?

No. Medigap supplements Original Medicare, including Parts A and B, and cannot be used with a Medicare Advantage plan. If you return to Original Medicare from Medicare Advantage, confirm your Medigap eligibility before ending existing coverage.

Do Medigap plans include prescription drug coverage?

Medigap policies generally do not include outpatient prescription drug coverage. If you want drug coverage with Original Medicare and Medigap, you can enroll in a separate Medicare Part D prescription drug plan.

Are all Medigap Plan G policies the same?

In most states, Medigap plans with the same letter offer the same standardized core benefits. Plan G benefits are generally the same across insurers, but premiums, discounts, rate-setting methods, and customer service can vary by carrier.

Have Questions?

Speak with a licensed insurance agent

1-877-436-2343

TTY users 711

Mon-Fri: 8am-9pm ET

Find & Compare Plans Online

Speak with a licensed insurance agent

1-877-436-2343TTY 711

Mon-Fri: 8am-9pm ET

ZRN Health & Financial Services, LLC, a Texas limited liability company

MedicarePartCPlans.org
1200 Lakeway Dr #17A
Austin, TX 78734

About Us | Editorial Policy | About the Author | Sitemap
TERMS & CONDITIONS | PRIVACY POLICY

This website and Medicare Supplement Insurance plans are not affiliated or connected with the Federal Medicare program or any other government agency. We do not offer every plan available in your area. Currently we represent 193 organizations which offer 4,624 products in your area. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Program (SHIP) to get information on all of your options. Data represented is for the plan year 2024. MedicarePartCPlans.org is a website owned and operated by ZRN Health & Financial Services, LLC, a Texas limited liability company. *You must continue to pay your Medicare Part B premium. $0 premium plans may not be available in all areas. Not all plans offer all benefits mentioned. By submitting your information in the form and clicking ‘Find Plans’, you agree to this site’s privacy policy and expressly consent to be contacted at the number entered in the form (including a wireless number if provided) by insurance professionals or other partners offering related offers that might be of interest to you by phone or email. You understand that these calls may be generated using an automatic telephone dialing system, a pre-recorded message or artificial voice, or by sending SMS messages. Your telephone company may impose additional charges on the subscriber for such messages. You understand that you are not required to provide this authorization to purchase goods or services. Receiving quotes through our website is always free and you are under no obligation to purchase any goods or services as a result of this request. The Medicare plans represented are PDP, HMO, PPO or PFFS plans with a Medicare contract. Enrollment in plans depends on contract renewal. Enrollment in a plan may be limited to certain times of the year unless you qualify for a special election or enrollment period or you are in your Medicare Initial Election Period. Deductibles, copay and coinsurance may apply. We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE (TTY users should call 1-877-486-2048) 24 hours a day/7 days a week to get information on all of your options.