Despite what you might think, you don't have to wait until you're 65 to sign up for Medicare. Your Initial Enrollment Period (often referred to as “IEP”) is actually a 7-month “window” around your 65th birthday during which time you can sign up for Medicare.
Inital Enrollment Period
Your Intial Enrollment Period includes the three months before the month in which you turn 65, the month that you turn 65, and the three months following the month in which you turned 65. It's important to note that your Medicare coverage will begin depending on when within your 7-month window you sign up.
If you sign up for Medicare Part A and/or Medicare Part B during the first 3 months of your Initial Enrollment Period, your coverage begins on the first day of the month in which you turn 65.
Example: Your 65th birthday is on May 20th. If you sign up for Medicare in February, March or April then your coverage will start on May 1st.
The only exception to this rule occurs when your birthday falls on the first of the month. When this happens Medicare essentially treats it as if your birthday took place in the previous month. So, if your birthday is on May 1st Medicare treats it as an April birthday and your seven-month window is shifted accordingly.
Example: If your birthday is on May 1st then your seven-month window would actually start in January instead of February. In this case, if you were to sign up for Medicare in January, February or March your coverage would begin on April 1st, a full month before your actual May 1st birthday.
When coverage starts if you don't sign up during the first 3 months of your IEP :
If you sign up:
The month you turn 65
1 month after you turn 65
2 months after you turn 65
3 months after you turn 65
Your Coverage Begins:
1 month later
2 months later
3 months later
3 months later