The Initial Enrollment Period (IEP) starts three months before the month you turn 65 and ends three months after you the month you turn 65 . This gives you seven months to sign up for Medicare without facing late penalties. That does not mean that your Medicare benefits will start at the same time as someone else.
When you sign up in the first three months of your IEP, Medicare coverage starts the month you turn 65. When you sign up in your birth month, benefits start the next month. However, you have to wait two months for coverage when you sign up one month after your birthday. You could be without coverage for three months if you wait to sign up two or three months after you turn 65. For most people, this applies only to Part B since Part A premiums are free for people who worked 40 quarters (10 years) in Medicare-taxed employment.