Medicare Supplement (Medigap) Open Enrollment Period
The Medicare Supplement Open Enrollment Period is a six-month window during which you may choose any Medicare Supplement (Medigap) plan.
During your Medicare Supplement Open Enrollment Period, insurance companies must issue you a Medicare Supplement (Medigap) policy without asking any health questions. Your Open Enrollment Period only occurs once, and if you miss this window, you may have trouble getting supplemental health insurance coverage down the road.
Therefore, applying for a Medicare Supplement insurance policy is best when you are first eligible to protect against hefty out-of-pocket costs and ensure coverage.
Navigating Medicare can feel overwhelming, especially when you’re trying to make sense of deadlines, rights, and which plan might protect your future best. If you’re approaching Medicare eligibility or helping a loved one through the process, understanding the Medigap Open Enrollment Period is essential – it’s a one-time opportunity to secure guaranteed coverage at the best price, no matter your health history.
In this guide, we’ll explain when Medigap Open Enrollment occurs, what protections it offers, what to expect if you miss it, and which plans seniors are choosing most often today.
What Is the Medigap Open Enrollment Period?
The Medigap Open Enrollment Period (OEP) is a unique 6-month window that gives you a one-time opportunity to enroll in the Medicare Supplement plan of your choice, with no health questions asked.
It begins the month you are both:
- 65 or older, and
- Enrolled in Medicare Part B
Let’s say you turn 65 in June and your Part B coverage also begins in June. Your Open Enrollment window will run from June 1 to November 30.
During this time, insurance companies cannot deny you coverage or charge you more based on pre-existing conditions. It’s the most flexible and cost-friendly moment to lock in your Medigap plan.
And here’s the kicker: this window does not repeat. If you delay or miss it, future applications may come with limitations. That’s why this six-month period is often referred to as your “once-in-a-lifetime chance” to enroll hassle-free.
What Are Guaranteed Issue Rights?
When you’re in your Medigap Open Enrollment window, you have what’s called guaranteed issue rights. These are exactly what they sound like – your right to buy a Medigap policy, guaranteed.
This means:
No medical underwriting
No coverage denial
No premium hikes based on your health
This protection is incredibly valuable, especially for people with chronic health conditions or a history of hospitalizations, who might otherwise face rejection or steep premiums when applying for coverage. You can select any standardized Medigap plan available in your state, from Plan A to Plan N.
Think of guaranteed issue rights as your backstage pass: You walk straight in, skip the line, and choose the plan you want – no questions asked.
Other Times You May Qualify for Guaranteed Issue
If you missed your Open Enrollment window, don’t panic – a few life events can trigger special guaranteed issue rights.
For example, you may qualify if:
- You move out of your Medicare Advantage plan’s service area
- Your Medicare Advantage plan drops coverage or exits your region
- You lose group health coverage from an employer or union
- Your current Medigap insurer goes out of business or misleads you
These rights usually last for 63 days from the qualifying event, and while they don’t always offer access to every plan, they do protect you from health-based denials. Typically, you’ll be able to enroll in Plans A, B, C, F, K, or L during one of these special periods, depending on availability in your state.
If life throws you a curveball, it’s reassuring to know there’s still a path to coverage – even if it’s more limited than your initial OEP.
Because there are so few situations where guaranteed issue rights apply outside of your enrollment window, the Medicare Supplement plan you buy is likely the plan you’ll have for the rest of your life, so working with an experienced agent is critical in order to take into account both current and possible future healthcare needs.
What Happens If You Apply After the Open Enrollment Window?
Once your six-month Medigap OEP has passed, you’re technically free to apply for a Medicare Supplement plan – but it comes with caveats.
Most significantly, you will likely face medical underwriting. That means:
- Insurance companies can ask about your health history
- They can deny your application
- Or charge higher monthly premiums based on existing conditions
This can be a serious barrier for individuals with diabetes, heart disease, a recent surgery, or any number of chronic health conditions.
Additionally, even if you’re approved, your policy might exclude coverage for certain pre-existing conditions for the first six months.
If you’re healthy now but on the fence about whether to get Medigap, don’t wait until something changes. Lock in coverage during your OEP when approval is guaranteed and rates are most affordable.
Other Enrollment Opportunities
If you are turning 65 in the near future:
You may apply for Medicare up to three months before your 65th birthday. Once you receive your Medicare card, you may apply for a Medigap (Medicare Supplement) policy.
Some insurance carriers allow you to apply for Medigap insurance up to six months before your Part B becomes effective. The company will treat your application as if you were already in your Medicare Supplement Open Enrollment Period and will not ask questions about your health conditions.
However, you will not receive any benefits from your Medigap policy until you turn 65 and your Part B becomes effective.
If you are under 65 with a qualifying disability:
You have two open enrollment periods if you are under 65 and have Medicare coverage due to end-stage renal disease (ESRD), amyotrophic lateral sclerosis (ALS), or another qualifying disability.
The first open enrollment period begins the month your Medicare becomes effective and continues for six months. Then, when you turn 65, you will have a second six-month open enrollment period that starts the first day of your birth month.
Important: Each state sets its own rules to determine whether disabled Medicare beneficiaries under age 65 are guaranteed enrollment in supplemental coverage. Medicare supplement coverage is not guaranteed in all states for this situation. Please check with a licensed insurance agent for more information.
If you already have group health coverage through an employer or union:
Some Medicare beneficiaries over 65 have group health coverage through an employer or union because they (or their spouse) are still working. Those seniors might want to delay enrolling in Medicare Part B.
Group health plans frequently provide benefits similar to Medicare Supplement insurance, so a Medigap policy is unnecessary. When you retire and your group coverage ends, you may enroll in Part B without a late penalty.
Once your Part B becomes effective, you have six months to buy a Medigap plan. After that, the insurance carrier can require you to answer health questions.
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Pro tip:
Certain states have year-round open enrollment, so it is wise to work with a licensed insurance agent who can inform you of the status of open enrollment in your state.
Common Mistakes People Make During Their Medigap Open Enrollment
The Medigap Open Enrollment Period is a powerful opportunity – but it’s easy to make missteps, especially when you’re new to Medicare. One of the most common errors is assuming the enrollment period comes around every year. It doesn’t. Once your six-month window closes, your ability to enroll without health screening may disappear for good.
Another frequent pitfall? Choosing a plan based solely on its low monthly premium. It may seem like a good deal in the short term, but a cheaper plan often comes with higher out-of-pocket costs – and fewer benefits – when you actually need care. That trade-off can become financially painful down the line.
Some people also mistakenly believe that Medigap plans cover prescription drugs. They don’t. If you need drug coverage, you’ll need to enroll separately in a Medicare Part D plan. Overlooking this can leave you facing a late enrollment penalty and unexpected pharmacy bills.
Finally, many Medicare enrollees fail to shop around. Even though Medigap benefits are standardized, prices can vary widely between insurance companies for the same exact plan. Not comparing costs is like paying full price when a sale is going on next door.
Can You Switch Medigap Plans Later?
Let’s say you enrolled in Plan K during your Open Enrollment because the premium fit your budget, but a few years later, you’re managing a chronic condition and want more robust coverage like Plan G. Can you switch?
Technically, yes. But outside your Open Enrollment Period, you no longer have guaranteed approval. That means insurance companies can (and often do) require medical underwriting. If your health has changed, you might face higher premiums, coverage exclusions, or outright denial.
Some people do get lucky. If they’re still in excellent health, they may pass underwriting and make the switch. But many aren’t so fortunate, especially if they wait too long to reconsider. That’s why choosing the right plan during your first enrollment window is so important – upgrading later is not always easy.
There are a few exceptions. States like New York and Connecticut allow you to change Medigap plans at any time with guaranteed issue rights. Others, like California and Oregon, offer birthday rules that let you switch annually without underwriting. But for most people, your first choice is your best shot, so choose wisely.
How to Prepare for Enrollment the Right Way
Approaching your Medigap Open Enrollment window without a plan can be stressful. But with a bit of preparation, you can approach it with confidence and clarity.
#1. Start by reviewing your current healthcare needs. Think about how often you visit the doctor, whether you have ongoing conditions, and if you expect new medical needs in the near future. This will help you narrow in on the level of coverage you need – and avoid over- or under-insuring yourself.
#2. Next, gather the right paperwork. You’ll need your Medicare card, showing your Part A and Part B effective dates, and a list of your healthcare providers and prescriptions. Knowing which doctors you want to keep seeing can help ensure your plan choice doesn’t disrupt your care.
#3. Then, take some time to compare prices across multiple insurers. Even though Plan G covers the same benefits no matter who you buy it from, premiums can vary significantly by company and ZIP code.
#4. Finally, don’t hesitate to consult a licensed Medicare insurance agent. We’re happy to help guide your decision and make sure you understand every part of the process, at no extra cost to you.
Most Popular Medigap Plans
Medicare Supplement plans are standardized, so Plan G from one company offers the same benefits as Plan G from another. But popularity can give you helpful insight into which plans deliver the best balance of value, protection, and peace of mind.
Here’s a snapshot of the most popular Medigap plans among today’s enrollees:
| Plan | Enrollment Share (2024) | Why It’s Popular |
|---|---|---|
| Plan F | 41% (closed to new enrollees) | Offers full coverage of all Medicare-approved costs, including the Part B deductible. Only available to those who qualified for Medicare before Jan. 1, 2020. |
| Plan G | 34% and growing | The most comprehensive plan available to new enrollees. Covers nearly everything except the Part B deductible. Great for those who want predictability and strong protection. |
| Plan N | 12% and rising | Offers solid coverage with slightly lower premiums, balanced by modest copays for doctor and ER visits. A strong option for relatively healthy seniors. |
| Plan K / L | <2% each | Lower premiums with cost-sharing and annual out-of-pocket caps. Good for budget-conscious individuals willing to share expenses. |
| High Deductible Plan G | Growing slowly | Offers the same benefits as Plan G, but with a high annual deductible ($2,870 in 2025) in exchange for lower monthly premiums. Best for healthy seniors who want protection from major expenses. |
Note: Plan G continues to gain momentum among new Medicare enrollees as the best all-around option, especially for those who want simplicity, consistency, and fewer out-of-pocket surprises.
How Medigap Open Enrollment Differs from Medicare Advantage Enrollment
It’s easy to confuse Medicare’s many enrollment periods – after all, they sound similar and often happen around the same time of year. But here’s an important distinction: the Medigap Open Enrollment Period is not the same as the Medicare Advantage Annual Enrollment Period.
Your Medigap Open Enrollment Period happens only once, beginning when you’re both 65 or older and enrolled in Medicare Part B. From that moment, you have six months to sign up for a Medigap plan with guaranteed approval, no matter your health history. After that, the door to guaranteed coverage begins to close.
By contrast, Medicare Advantage has annual enrollment windows. Every fall, from October 15 to December 7, you can review and switch Advantage plans. These recurring opportunities don’t exist with Medigap, which makes its one-time Open Enrollment Period even more critical to get right the first time.
In short: if you want the flexibility and broad coverage of a Medigap plan, don’t assume you’ll have another shot next year. You likely won’t.
Bottom Line: Enroll Early, Protect More
Your Medigap Open Enrollment Period is a short window with long-term benefits. It’s your best shot at getting comprehensive Medicare Supplement coverage without the fear of rejection, high premiums, or pre-existing condition exclusions.
Whether you’re considering a budget-friendly option like Plan N or High Deductible G, or you want the security and stability of Plan G, enrolling during your OEP gives you the freedom to choose without barriers.
Final Takeaways:
- The 6-month Open Enrollment Period begins when you’re 65+ and enrolled in Medicare Part B.
- You have guaranteed issue rights during this time – no underwriting, no rejections, no price penalties.
- Outside the OEP, getting Medigap becomes harder, especially if your health changes.
- The most popular plans – G, N, and High Deductible G – offer a range of options to suit different needs and budgets.
Don’t leave your healthcare future up to chance. Mark your calendar, explore your plan options, and make your decision during the time when the choice – and the protection – is entirely yours.
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Let us guide you through this process so that your chosen plan best suits your needs.
FAQs
- Does my Medigap Open Enrollment Period start automatically when I turn 65?
- Can I enroll in Medigap before my Open Enrollment Period begins?
- What happens if I enroll in a Medicare Advantage plan first - can I still use my Medigap Open Enrollment Period later?
- Are Medigap plans cheaper if I enroll during my Open Enrollment Period?
- Does Medigap Open Enrollment apply if I’m under 65 and disabled?
- If I move to another state after enrolling in Medigap, do I get a new Open Enrollment Period?
- What if I miss the six-month window but I’m still healthy? Should I apply anyway?
