When Can You Buy a Medigap Policy?

Timing matters more with Medigap than almost anything else about it. Buy at the right moment and insurers generally can’t turn you down. Buy at the wrong moment, and they can — legally, and often will if your health history gives them a reason to.

The window that matters most: Medigap Open Enrollment

This is a one-time, six-month window that starts the month you’re both 65 or older and enrolled in Medicare Part B. During these six months, you have guaranteed-issue rights — an insurer selling Medigap policies in your state cannot deny you coverage, charge you more, or make you wait for a pre-existing condition to be covered, no matter what’s in your medical history.

This window does not repeat. It happens once, and it starts counting down automatically the moment you have Part B, whether or not you’re paying attention to the calendar.

What happens if you miss it

You can still apply for a Medigap policy at any time in most states. Outside your open enrollment window, though, insurers can use medical underwriting — meaning they can ask about your health history and legally deny you coverage or charge higher premiums based on the answers. This is the single biggest reason to not simply “get around to it later.”

Guaranteed-issue rights outside the main window

Certain life events trigger their own guaranteed-issue periods regardless of your age or when you first enrolled — for example, if your Medicare Advantage plan leaves your area, if your employer coverage ends, or in a handful of other specific circumstances defined by federal and state law. If one of these applies to you, you may have a fresh guaranteed-issue window worth confirming before you assume you’ve missed your chance.

A few states change the rules in your favor

A small number of states require insurers to offer at least some Medigap policies on a guaranteed-issue basis year-round, or provide an annual window to switch plans without underwriting. Whether this applies to you depends entirely on where you live, and it’s worth confirming directly rather than assuming national rules apply everywhere.

The practical takeaway

If you’re approaching 65, mark your Part B effective date and count six months forward. That window is worth building your decision-making around, not squeezing into whenever you happen to get to it.

This page is general educational information, not insurance advice specific to your situation. Enrollment rules can vary by state — confirm specifics for your location. See our full disclosure.