Other than your initial enrollment period, Medigap does not have an open enrollment period. For most people, when they turn age 65 and sign up for Medicare Part B, their initial enrollment period starts. During that 6 month period you can sign up for any Medicare supplement plan without providing evidence of insurability.
But you are allowed to buy or change your Medigap plan at any time of the year.
But you are allowed to buy or change your Medigap plan at any time of the year.