When Will My Medigap Start?

Learn your Medigap effective date

by Amy De Vore+ on Dec 26, 2016 | 2 Comments

Medicare Supplement, also known as Medigap, is supplemental insurance that fills in the gaps of Original Medicare. If you have decided that a Medigap policy is the right insurance for you, then you will want to sign up when you’re first eligible.

What is the Medigap Initial Enrollment Period?

Medigap’s initial enrollment is a one-time 6-month application time period that guarantees that you will be approved for a Medigap.  If you miss the initial enrollment window you will usually have to answer health questions and could be denied coverage.

When is the Medigap Initial Enrollment Period?

Medigap initial enrollment usually starts the first of the month when you turn 65*, and runs for six months.  You can, however, apply up to three months before your 65th birthday so that your Medigap start date will match your Medicare Part B start date.

If you chose to delay your Medicare Part B enrollment because you have creditable coverage (usually job-based insurance), the 6 month initial enrollment period begins on your Part B effective date. .  Try our Medicare deadline calculator to help you figure out when to apply for Medicare health plans.

When you sign up for Medigap*: When your Medigap effective will begin:
3 months before your 65th birth month The 1st of your 65th birth month
During your birth month The 1st of the following month
During your 65th birth month The 1st of the following month
During the 5 months after your 65th birth month The 1st of the following month

*This whole chart assumes your Part B effective date is active

Learn More about Medigap Get a Medigap Quote

What if you Miss the Medigap Initial Enrollment Period?

If you miss your initial enrollment period you’ll usually have to go through medical underwriting unless you live in CT and NY   or you qualify for a few special enrollment. Medical underwriting just means you’ll have to answer medical questions before you will be approved. If you have certain preexisting conditions, you could be denied or charged more. Don’t give up hope! There are some companies that are easier to get approved from than others. We at Senior65 consider ourselves the Medigap enrollment experts. We can help you choose a company that will work best for your health and financial needs, call our licensed independent insurance agents at 800-930-7956.


  • If you were eligible for Part B early due to a disability, you will have a new initial enrollment period when you turn 65.
  • If your birthday falls on the first of the month both your Medicare part B and Medigap plan can start the first of the month preceding your 65th birthday
  • If you chose not to delay Medicare Part B, but have creditable coverage, when you leave that coverage you will have 63 days to enroll in a handful of Medigap plans


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Reader Comments and Questions

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By Diane on May 13, 2019

I will be eligible for medicare on July 1 (my birthday is July 19). When I called the insurance company that I wanted to get my Medigap through they told me that I would not be eligible until August 1st. Do all insurance companies do this? Thank you very much!

Hello Diane,
That's a definite no. You should be able to enroll in Medigap up to three months before July 1st aka your Part B Effective Date.

Give us a call and we can help you enroll at no cost.
-Michelle from Senior65.com

By James on March 31, 2019

If my birthday is August 1st, can I begin my Medicare Part G July 1st?

YES!!! Given that your birthday is on the 1st of the month you should be able to start your Medicare Part B and your Medigap Plan a month prior to your birthday.

We can start the application process as early as May 1st. When you are ready to enroll in Medigap, please give us a call. Our service is free of charge to you.
-MIchelle from Senior65.com

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