Blog / Medigap

When is my Medigap open enrollment period?

Six months from the month your Part B starts. It is the most important window in Medicare and it does not come back.

Updated August 17, 2026 · 3 min read

Your Medigap open enrollment period runs six months, starting the first month you are both 65 or older and enrolled in Part B.

It is separate from every other Medicare window, it is not the same as Annual Enrollment in October, and almost nobody is told about it 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.
• No company can impose a waiting period for a pre-existing condition if you had prior creditable coverage.

That protection is called guaranteed issue, and during these six months it is absolute.

What happens after it closes

In Texas, outside a guaranteed issue situation, Medigap insurers can medically underwrite. They can ask about your health history, charge you more, or decline you outright.

The window is tied to Part B, not your birthday

It starts when Part B starts. If you delayed Part B because you were working past 65, your Medigap window has not started yet. It begins when Part B does.

That is genuinely useful. Someone who works until 70 with employer coverage gets a full, fresh, guaranteed issue Medigap window at 70. See working past 65.

Other times you get guaranteed issue

Outside the six month window, certain 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
• Trial right: you joined an Advantage plan when first eligible at 65 and drop it within twelve months
• Trial right: you dropped a Medigap policy to try Advantage for the first time and return within twelve months
• Your employer or union coverage ending, in certain circumstances
• Your insurance company misled you or went out of business

These rights are time limited, usually 63 days from the qualifying event. Do not sit on them.

If you qualify for Medicare before 65

People who qualify through disability have a different situation, and state rules matter more here. Ask before assuming you have no options, because what is available to you under 65 differs from the standard picture and it changes when you turn 65.

What to do with your window

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

See all Medicare enrollment windows.