Medicare comes with several different enrollment periods. The window you use depends on the part of Medicare for which you’re looking to sign up. Some windows overlap to make coordination of coverage simpler. Below, we’ll help you determine when you should be enrolling, based on which part of Medicare you need, your eligibility, and other factors.

When Do I Apply for Medicare Parts A and B?

When you can apply for Original Medicare (Part A and Part B) depends on when you first become eligible. Your Initial Enrollment Period happens around your 65th birthday. If you’re eligible for Medicare due to a disability before you turn 65, you’ll get two Initial Enrollment Periods and the second will happen when you turn 65.

As your first chance to enroll, your Initial Enrollment Period starts three months before the month you either turn 65 or collect SSDI for 24 months. The first day of this window is the first day of that month. It then lasts through the last day of the third month after you become eligible.

The second enrollment period you can use to apply for Parts A and B is the General Enrollment Period. This enrollment period happens each year between January 1 and March 31. If you enroll during this window, your coverage begins on July 1.

The only other time to apply for Parts A and B would be a Special Enrollment Period. Special Enrollment Periods depend on your circumstances, and you may be eligible if you recently lost group coverage through your employer.

When Do You Apply for Medicare Advantage?

If you plan to apply for Part C of Medicare (an Advantage plan), you’ll need to enroll in Part A and Part B first. Then, you can enroll during your Initial Coverage Election Period (ICEP), which happens during your Initial Enrollment Period. When you enroll in Original Medicare, your ICEP starts three months prior to your Part B effective date.

Each year, you can also apply for an Advantage plan during the fall Annual Enrollment Period between October 15 and December 7. Lastly, you can enroll instead (or change your Advantage plan if you aren’t happy with it) during the Medicare Advantage Open Enrollment Period (January 1 through March 31). Like with Parts A and B, you can also qualify for a Special Enrollment Period should circumstances arise where you are eligible.

When Should I Apply for Medicare Part D?

When you choose to enroll in a Part D prescription drug coverage plan to pair with your Original Medicare, you’ll have two main options. These windows are your Initial Enrollment Period when you sign up for Parts A and B and the Annual Enrollment Period. 

Since most Advantage plans include prescription drug coverage, the Annual Enrollment Period also gives those with Original Medicare a chance to add or change drug coverage. Each fall, you can evaluate plans and decide on new Part D coverage to start on the first of the following year. Otherwise, you’ll need to qualify for a Special Enrollment Period through events such as losing the prescription drug coverage through your employer or spouse. 

Annual Enrollment Period


This enrollment window begins 3 months before you turn 65 and ends 3 months after you turn 65.

Annual Enrollment Period


This period begins on October 15th and will run through December 7th every year.

Special Enrollment Period


You are eligible for a SEP after a qualifying event (such as losing coverage or relocating).

Jagger Esch

Medicare Expert

Jagger Esch is the Medicare expert for MedicareFAQ and the founder, president, and CEO of Elite Insurance Partners and Since the inception of his first company in 2012, he has been dedicated to helping those eligible for Medicare by providing them with resources to educate themselves on all their Medicare options. He is featured in many publications as well as writes regularly for other expert columns regarding Medicare.

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