As of 2015, a person who is over 65 and not yet enrolled in Medicare Part A or Part B is allowed to sign up during the General Enrollment Period between January 1 and March 31, according to Medicare.gov. People who experience special circumstances are given more flexibility.
Special Enrollment Periods are open when certain life events occur, such as moving, losing other insurance coverage or being released from incarceration, Medicare.gov explains. Though specific rules vary depending upon the situation, people typically have two months to sign up for Medicare after their incident.
When people turn 65, they are given seven months to enroll in Medicare, states Medicare.gov. This includes the three months prior to the birthday month, the birthday month and the three months following it.