When to enroll in Part D

Medicare Part D enrollment

If you need to enroll in Medicare Part D for the first time, typically you will do so either during your Initial Enrollment Period (IEP), the Fall Open Enrollment Period, or if you qualify for a Special Enrollment Period (SEP). Additionally, you must:

  • Have Part A and/or Part B
  • And, live in the Part D plan’s service area

Your Part D IEP is usually the same as your Medicare IEP: the seven-month period that includes the three months before, the month of, and the three months following your 65th birthday. For example, let’s say you turn 65 in May. Your IEP runs from February 1 to August 31.

The date when your Part D coverage begins depends on when you sign up:

  • Enrolling during the first three months of the IEP means coverage begins the first day of the fourth month.
  • Enrolling during the fourth month of the IEP or any of the three months afterwards means coverage begins the month following the month of enrollment.

You should enroll in Part D as soon as you are eligible to avoid a potential late enrollment penalty (LEP) and gaps in coverage. If you do not enroll in Part D during your IEP, you can also enroll in or make changes to Part D coverage during the Fall Open Enrollment Period—but you may have a late enrollment penalty if you are using Fall Open Enrollment to enroll in Part D for the first time.

Under certain circumstances, you may have an SEP to enroll in a Part D plan, including if you:

If you enroll in premium Part A and/or Part B during the General Enrollment Period (January 1 to March 31 of each year), you have an SEP to join a Part D plan starting the date you submit your application for premium Part A or Part B. The SEP lasts for the first two months of enrollment in premium Part A or Part B. Your Part D coverage would begin the first day of the month following the month you enroll in Part D.

Note: If you are enrolled in Medicare because of a disability and currently pay a premium penalty, once you turn 65 you will no longer have to pay the penalty. This is because you will qualify for a new Part D IEP when you turn 65.