Medigap Open Enrollment
The Medigap Open Enrollment Period is a six-month window starting the month you're 65 or older and enrolled in Medicare Part B, during which you have a guaranteed right to buy any Medigap policy sold in your state, regardless of your health status. After this period, your ability to buy a Medigap policy may be limited and it could be more expensive.

The Medigap Open Enrollment Period is a six-month period that starts on the first day of the month in which you're both 65 or older and enrolled in Medicare Part B. For example, if you turn 65 and enroll in Part B in June, the best time for you to buy a Medigap policy is from June to November.
During this period, you have a "guaranteed-issue right" to buy any Medigap policy sold in your state regardless of your health status. Insurance companies can't refuse to sell you a policy, charge you more due to pre-existing health conditions, or make you wait for coverage to start. This is beneficial for those who might otherwise be denied insurance or charged more due to their health status.
Once this six-month period ends, you may not be able to buy a Medigap policy, and if you're able to buy one, it may cost more. That's why it's crucial to buy a Medigap policy during the open enrollment period to secure the most advantageous terms.
Remember, the Medigap Open Enrollment Period is different from the Annual Medicare Open Enrollment Period (October 15 - December 7), during which people can change their Medicare health plans and prescription drug coverage for the following year.