You may also apply for a Medicare Advantage plan during a Special Enrollment Period (SEP). These include, but are not limited to, the following: The 3 months before, the month of, and the 3 months following your initial eligibility (usually when you reach 65), moving into a new county, leaving your group health plan, loss of your current plan, eligibility for Medicaid, and many more. To see if you qualify for a Special Enrollment Period call us for some friendly advice at (800) 921-0442.