When you are first eligible for Medicare you have a 7-month Initial Enrollment Period to sign up for Part A and/or Part B. Example For example, if you're eligible for Medicare when you turn 65, you can sign up during the 7-month period that: Begins 3 months before the month you turn 65 Includes the month you turn 65 Ends 3 months after the month you turn 65 General Information If you aren’t automatically enrolled, you can sign up for free Part A (if you’re eligible) any time