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When Can I Sign Up for Medicare Supplement Insurance (Medigap)?

Wondering when you can enroll in a Medicare Supplement Insurance Plan? Also known as Medigap, these plans are sold by private insurers to help bridge gaps in Original Medicare. You can count on a Medigap policy to make up for costs such as deductibles, copayments and coinsurance that you could be responsible for.

What you’ll learn:

When’s the Best Time to Buy a Medigap Plan?Jump to
What if I Miss my Medigap OEP?Jump to
Enrolling in Medigap Under 65Jump to
Enrolling in Medigap with Pre-Existing ConditionsJump to
Medigap OEP vs Medicare AEPJump to

When’s the Best Time to Buy a Medigap Plan?

During your six-month Medigap Open Enrollment Period (OEP), when you’ll get a better selection and more competitive prices. 

Since insurers aren’t allowed to use medical underwriting during open enrollment, they can’t charge you more for a plan, refuse to sell you a plan, or make you wait for your coverage to kick off (unless you have a pre-existing condition – more on that below).

Medigap open enrollment period

Your Open Enrollment Period kicks off on the first month that you have Medicare Part B (basic medical insurance) and are 65 or older. This is also known as your Part B effective date.  

It may be easier to think of it this way: If your Part B effective date is January 1, you should make a point of buying Medigap any time from January 1 to June 30.  

Mark your calendar – while some states have other open enrollment periods, you may find that it’s hard to get a well-priced Medigap policy outside of your standard enrollment time.

What if I miss my Medigap OEP?

You can apply for a Medigap policy at any time. Keep in mind, however, that you can’t repeat or change your Medigap Open Enrollment Period. If you buy outside this period, your plan may cost more – if you can get one at all.

There are several other situations that would give you guaranteed-issue rights outside of your OEP. These may vary depending on what state you live in. So, it’s important to do your research or speak to a licensed agent who can confirm if you qualify for these rights.  

That said, if you miss your Medigap Open Enrollment Period, and are concerned about being approved for a Medigap Plan, you also have the option of Medicare Advantage.  

Medicare Advantage does not require medical underwriting. So, you don’t have the risk of being denied coverage like with Medigap. If you’re worried about being able to choose your own provider, know that their PPO plans let you do this, though sometimes at a higher cost. 

Learn more about Medigap vs Medicare Advantage here.  

When should I enroll in Part B?
To enroll in Medigap, you need Medicare Part B first. If you’re 65 or older, remember that you should enroll in Part B when you first become eligible to avoid a late penalty. When you enroll in Part B, that’s when your Medigap Open Enrollment Period starts.  

If you have group health coverage through an employer or union, it’s probably best to hold off on enrolling in Part B because the insurance you carry is probably similar to Medigap. When this coverage runs out, you can enroll in Part B without any late fees. Don’t buy anything before you need it! 

If you do enroll in Part B while you’re still employed at age 65 and miss your Medigap Open Enrollment window, you may qualify for guaranteed-issue rights when you retire.  

Enrolling in Medigap Under 65
If you’re under 65 and eligible for Original Medicare because of a disability or End-Stage Renal Disease, you may not be able to buy Medigap until you turn 65.  

That said, some state laws do require companies to sell you a Medigap policy if you’re under 65. It may cost you more than normal, though.
In this case, your Medigap OEP will still start on your Part B effective date.

States that allow Medigap under 65

The following states will allow you to apply for a Medigap policy under the age of 65: 

  • Arkansas 
  • California 
  • Colorado 
  • Connecticut 
  • Delaware 
  • Florida 
  • Georgia 
  • Hawaii 
  • Idaho 
  • Illinois 
  • Kansas 
  • Kentucky 
  • Louisiana 
  • Maine 
  • Maryland 
  • Massachusetts 
  • Michigan 
  • Minnesota 
  • Mississippi 
  • Missouri 
  • Montana 
  • New Hampshire 
  • New Jersey 
  • New York 
  • North Carolina 
  • Oklahoma 
  • Oregon 
  • Pennsylvania 
  • South Dakota 
  • Tennessee 
  • Texas 
  • Vermont 
  • Wisconsin 

Enrolling in Medigap with Pre-Existing Conditions
If you have health issues, you may be worried that you won’t be able to get a Medigap policy. This isn’t true as you’re guaranteed to be able to buy one during your Medigap OEP. However, a Medigap insurer can still refuse to cover out-of-pocket costs for pre-existing conditions for up to six months. After your six-month waiting period, your condition will fall under Medigap coverage.  

All this said, you can minimize or outright shorten pre-existing condition waiting periods by purchasing Medigap during your Medigap Open Enrollment Period to replace what is considered creditable coverage – provided your coverage gap was 63 days or less. 

Creditable coverage is a health plan that provides equal or better coverage than what Medicare provides.
Some examples of creditable coverage include employer-provided group health plans from companies with 20 or more employees, union sponsored health plans and Federal Employee Health Benefits.  

Also, if you have a Guaranteed Issue Right – the insurer can’t institute a pre-existing condition waiting period. Guaranteed Issue situations include: 

  • Being in a Medicare Advantage Plan that is leaving Medicare or stops servicing your area, or you move out of the area. 
  • Leaving a Medicare Advantage Plan or dropping a Medigap plan because the company did not follow established guidelines. 
  • Having Original Medicare and a Medicare SELECT policy and moving out of the SELECT policy’s service area. 

Learn more about your Medigap rights with pre-existing conditions here.  

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Medigap Open Enrollment Period vs Medicare Annual Enrollment Period

Medicare’s Annual Enrollment Period (AEP) is oftentimes referred to as Open Enrollment Period. So, it can be easily confused with Medigap’s Open Enrollment Period. However, the two serve very different purposes. 

A one-time enrollment period, Medigap OEP automatically kicks off the first month you have Medicare Part B and are 65 or older. It runs for six months. During this time, you can enroll in a Medigap plan with no medical underwriting. 

The Medicare AEP, on the other hand, runs annually from October 15 to December 7. During these 7.5 weeks every year you can make changes to your existing Medicare coverage. However, there are no guaranteed-issue rights for Medigap during this time. Meaning, you’ll likely have to go through underwriting if you try to purchase a Medigap plan during AEP. 

There’s also the Medicare Advantage Open Enrollment Period which runs annually from January 1 to March 31.
You can only use this enrollment period if you already have a Medicare Advantage Plan.  


Meeting enrollment deadlines will help you get the right plan for you at the best price. While your Medigap Open Enrollment Period may be the best time to purchase a plan, we can help you apply for coverage even if you miss it. Regardless of your situation, our licensed agents can help you find a Medicare solution that matches your lifestyle.  

Interested in learning about the Medigap plans in your area? Call the number on this page to speak with an Ensurem licensed insurance agent.  

If you’d rather not speak with an agent, ask Emma! Your virtual Medicare assistant, Emma can help you compare Medigap plans, and in some cases even apply for plans, online.

Ready to Talk to an Expert But Don’t Know Where to Start? Here is a List of Questions You can ask to Help Get You Started.

  • When is the Medigap open enrollment period?
  • Can I switch from a Medicare Advantage Plan to a Medicare Supplement plan outside of the open enrollment period?
  • What factors should I consider when choosing an insurance company for my Medicare supplement insurance?
  • What is the difference between a Medicare supplement plan and a Medicare Advantage plan?
  • How does medical underwriting affect my eligibility for a Medicare supplement plan?
  • What happens if I miss my initial enrollment period for Medicare Supplement insurance?
  • As a Medicare beneficiary, what are my options if I want more coverage than what Original Medicare offers?
  • Can I buy a Medigap policy anytime or only during certain enrollment periods? What about an annual open enrollment period? Or special enrollment period?
  • How does a Medigap plan differ from Medicare Part A and Part B?
  • Are there any federal laws that protect my rights as a consumer when buying Medicare supplement insurance?
  • Will the Medigap coverage change if my health history changes?
  • Does a Medicare Supplement plan include prescription drug coverage or do I need to purchase that separately?
  • What are the benefits of Medicare Supplement Insurance over Original Medicare?
  • How does medical underwriting impact the cost of my Medicare Supplement insurance plan?
  • What do I need to know about the initial enrollment period for Medicare Supplement plans?
  • As a Medicare beneficiary, how can Medicare Supplement plans benefit me?
  • When is the Medicare Supplement open enrollment period and what can I do during this time?
  • What federal laws protect my rights when purchasing health insurance, specifically Medicare Supplement plans?
  • How does Medicare Supplement insurance integrate with my existing Medicare coverage?
  • Which is more beneficial for me – Medicare Advantage plans or Medicare Supplement plans?

Ensurem Trusted Expertise

Education is crucial in finding the right Medicare solution for you. With so many Medicare resources out there, it can be difficult finding a source you can trust. That’s why Ensurem has a Compliance Program dedicated to ensuring our Medicare content meets Centers for Medicare & Medicaid Services (CMS) regulations. So, you can rest assured you’re getting the information you need to make the right coverage decisions.

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Denise Austin, 65, Ensurem Ambassador

Best-Selling Author, Creator of Fit Over 50 Magazine

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