Enrolling is easier than you think. Once you’ve taken the steps to sign up for Medicare Parts A & B (also known as Original Medicare), you’ll be ready to enroll in additional coverage. You can do this during the Initial Enrollment Period. For Part C Medicare Advantage and Part D prescription drug plans, the Initial Enrollment Period spans a 7-month window. It begins 3 months prior to your 65th birthday, includes your birth month, and ends 3 months after you turn 65. For Medicare Supplement plans, you can enroll any time after turning 65; however, you have a 6-month window after turning 65 to enroll in a plan with automatic acceptance. After six months, underwriting may be required to qualify for a plan. This means that unless you have a Medigap protection that guarantees enrollment in a Medicare Supplement plan, you could be denied coverage if you’re not in good health.
The full Social Security retirement age varies based on the year you were born (age 66 for those born 1943 to 1954), but you're eligible for Medicare at age 65. You do not have to be retired to enroll. If you'll have employer-provided health coverage at age 65, contact your benefits administrator (typically part of your human resources department) to find out how Medicare will work with your current coverage.