People who turn 65 and are collecting Social Security benefits are automatically enrolled in Medicare Part B. If you’re not collecting Social Security benefits yet, you need to enroll online, over the phone, or in person.
Newly eligible Medicare beneficiaries can enroll from three months before the month of their 65th birthday to three months after the 65th birthday. This is called the initial enrollment period.
You should receive your Medicare card during the month before your 65th birthday.