The first time you become eligible for Medicare, you’ll be able to sign up for Part A and Part B during your initial enrollment period, which spans for seven months including the three months prior to the month you turn 65, the month you turn 65, and the three months following the month you turned 65. Use this online eligibility estimator tool from Medicare to determine the dates for your initial enrollment period. Many people sign up for Part A as soon as they turn 65 since it can be easy and typically free of charge. Many people also sign up for Part B during their initial enrollment period, but it may be more beneficial to wait depending on your situation. If you do not anticipate having group coverage through your own or your spouse's employer when you turn 65, think about signing up for Part B during your initial enrollment period so you don’t have to pay a late enrollment penalty. However, if you anticipate having group coverage through your own or your spouse’s employer when you turn 65, you may want to consider holding off on signing up for Part B until you’re no longer eligible for that group coverage. Just make sure to enroll in Part B within 8 months of that group coverage ending, otherwise you will get penalized for waiting too long and you’ll have to pay an additional fee.