Medicare has several enrollment periods, including:
Initial Enrollment Period (IEP)
This period begins three months before your 65th birthday and ends three months after. There are no penalties for signing up during this time, and you can also sign up if you apply for Social Security three months before or after your 65th birthday.
Special Enrollment Period (SEP)
This period allows you to make changes to your Medicare Advantage and/or Part D plan due to special circumstances. For example, if you were incarcerated and kept paying for your Part A and Part B coverage, you have two months after your release to join a plan.
General Enrollment Period
This period is January 1 through March 31 each year, and you can sign up if you missed the IEP or SEP. However, there is usually a penalty for signing up during this time.
Annual Enrollment Period
This period is October 15 through December 7 each year, and anyone can make changes to their coverage or enroll in a Medicare plan. For example, you can switch from Original Medicare to Medicare Advantage, or vice versa. Your new coverage will begin on January 1.