When Is Open Enrollment For Medigap Insurance? 
You have an initial open enrollment period when you 're new to Medicare -LRB- specifically , when you start Medicare Part B -RRB- . This is a 6-month window from your Medicare Part B effective date where you can buy any Medigap plan from any insurance company with no medical underwriting . Outside of your initial open enrollment period , you can buy a new Medigap plan at any time throughout the year -LRB- which is great for trying to lower your monthly premium - and since Medigap plans are standardized , you can lower your premium without losing benefits -RRB- . Medigap plans are not restricted to annual enrollment periods like MA & Part D plans are . Please note , you may have to answer health questions on the application to qualify for a new Medigap plan . I hope the information is helpful . Please feel free to contact me if you need help getting a Medigap plan set up for your Medicare insurance program or are looking to lower your monthly premium . Thanks very much . 