Can I Sign Up For Medicare Part B Late? 
Yes , however , the best time to sign up for Part B is during your initial enrollment period when you turn 65 . If you choose not to enroll in Part B when you 're first eligible , you can enroll during the General Enrollment Period - January 1st to March 31st of each year . When you do this , the effective date will be July 1st . You may be subject to a late enrollment penalty if you do n't sign up when you 're first eligible : an additional 10 % is added to your premium for every year you did not have the coverage . You can avoid this penalty if you qualify for a special enrollment period - the most common way this happens is coming off of a group plan . A special enrollment period is an 8-month window to enroll in Part B without the penalty being tacked on to the premium . If you enroll during this 8-month window , the effective date would become the first day of the following month . 