Blog / Medigap

When is my Medigap open enrollment period?

Six months, starting the month your Part B begins at 65 or later. It opens once, and in Texas it does not come back.

Updated September 3, 2026 · 3 min read · by Gerino Alejos

Your Medigap open enrollment period runs six months. It starts the first month you are both 65 or older and signed up for Part B, the part of Medicare that pays for doctor visits and care outside the hospital. It is not the same as the Annual Enrollment window in October, and it does not come back.

Medigap is a supplement, a separate policy you buy to pay bills that Original Medicare leaves to you. Almost nobody is told about this six month window at the moment it matters.

What the window gives you

• You can buy any Medigap policy sold in Texas.
• No company can refuse you.
• No company can charge you more because of your health history.
• If you had creditable coverage before, meaning health coverage that Medicare counts, no company can make you wait to cover a health problem you already have.

That protection has a name, guaranteed issue. It means no company can say no to you and no company can price you by your health. For these six months it holds without exception.

What happens after it closes

In Texas, once the window closes, a Medigap company can use medical underwriting unless you have a guaranteed issue right. Underwriting means the company reads your health history and decides. It can ask what you have been treated for, charge you more, or turn you down.

The window is tied to Part B, not your birthday

The clock starts when your Part B starts. If you put off Part B because you kept working past 65 and stayed on the employer plan, your Medigap window has not started yet. It begins the month Part B does.

So a person who works until 70 gets a full six month window at 70, with the same guaranteed issue protection. See working past 65.

Other times you get guaranteed issue

Outside the six month window, a few situations still protect you.

• Your Medicare Advantage plan leaves the area or loses its Medicare contract.
• You move out of your Advantage plan's service area, the counties where that plan is sold.
• You joined an Advantage plan when you were first eligible at 65 and you drop it within twelve months. Medicare calls that a trial right.
• You dropped a Medigap policy to try Advantage for the first time and you go back within twelve months. That is a trial right too.
• Your employer or union coverage ends, in certain situations.
• Your insurance company misled you or went out of business.

These rights do not last. In most cases you have 63 days from the event that gave you the right.

If you qualify for Medicare before 65

People who qualify through a disability are in a different spot, and state rules matter more here. Ask before you assume you have no options. What is open to you under 65 is not the standard picture, and it changes when you turn 65.

What to do with your window

1. Find the date your Part B started. It is printed on your Medicare card.
2. Count six months forward, and put the end date on a calendar.
3. Decide the big question, supplement or Advantage, before that date instead of after.
4. If you want a supplement, apply and have the approval in hand before the window closes.
5. If you go with Advantage instead, do it knowing the window has closed and what that means later.

See all the Medicare enrollment windows, then how to enroll in a supplement. If you are not sure when your Part B started, we will read your card with you and count the months. Call our McAllen office at (956) 687 3334, or use the ZIP form on this page.

Gerino Alejos

Licensed insurance agent · License 3128710 · NPN 18243381

Owner of McAllen Insurance Group, an independent agency on North 10th Street in McAllen. Works with clients across Hidalgo, Cameron and Starr counties on Medicare, Marketplace health, life and auto coverage. Se habla español.