Fall Open Enrollment, also known as the Annual Election Period, occurs each year from October 15 through December 7. During this period, you can change your Medicare coverage, and these changes will take effect January 1 of the following year. You can switch between Original Medicare (with or without a Part D plan) and Medicare Advantage; join a new Medicare Advantage Plan; and enroll in Part D for the first time if you did not enroll during your Initial Enrollment Period. (You may have to pay a Part D late enrollment penalty if you newly enroll in Part D during this time, unless you have had other creditable drug coverage.)