Understanding the Medicare Enrollment Periods

Medicare enrollment can be confusing and overwhelming. You may not understand what the process entails or know which deadlines are applicable. While the Annual Enrollment Period for 2025 began on October 15 and runs through December 7, there are several other time frames during which you can make changes to your plan. You may also still be able to sign up for Medicare if you missed the Initial Enrollment Period by waiting until the General Enrollment Period — or qualifying for a Special Enrollment Period. 

What are the Medicare Enrollment Periods?

Medicare has several different enrollment periods — and it’s important to distinguish between each of them. While the main enrollment period is referred to as “initial enrollment,” there are specific time frames for making changes once you have already signed up for coverage. The following are several Medicare enrollment periods to be aware of:

Initial Enrollment Period (IEP) 

The Initial Enrollment Period (IEP) is the time frame around your 65th birthday when you first sign up for Medicare. It begins three months before the month you turn 65 and ends three months after. If you miss the IEP, you may have to wait until the General Enrollment Period (GEP) or the Special Enrollment Period (SEP) to obtain coverage.

Annual Enrollment Period (AEP) 

The AEP is the period between October 15 and December 7 of each year during which you can make changes to your Medicare plan. For instance, if you are enrolled in Part A and B, you can change to Medicare Advantage (Part C). You can also switch back to original Medicare and choose to add a Part D plan. If you already have a Part D prescription drug plan, you can switch to a different Part D plan or drop your Part D coverage.      

General Enrollment Period (GEP) 

The General Enrollment Period runs from January 1 through March 31 each year. It provides an opportunity to enroll if you are eligible but missed your initial enrollment window and don’t qualify for a Special Enrollment Period. You may have to pay a late enrollment penalty for Part B and potentially for Part A if you pay a premium.

Medicare Advantage Open Enrollment Period (MA OEP) 

The Medicare Advantage Open Enrollment Period (MA OEP) is the period between January 1 and March 31 of each year when people who already have Medicare can change their Medicare Advantage Open or Part D plans. You can also switch back to original Medicare. If you return to original Medicare, you can enroll in a separate Part D plan. 

Special Enrollment Period (SEP) 

The Special Enrollment Period allows you to join a Medicare Advantage plan with or without drug coverage, or switch to another plan when certain situations happen in your life. For instance, if you move or lose other coverage, you may be able to enroll outside the standard period.  

What Happens if You Miss the Enrollment Period Deadline?

If you miss a Medicare enrollment period, you may incur a penalty — or have to wait until the next applicable enrollment period to make changes to your coverage or sign up. In the event you miss your initial enrollment period, you can still enroll in Medicare Part A and Part B during the General Enrollment Period which happens every year between January 1 through March 31. Your coverage would start the month after you enroll. However, if you are late, you may have to pay a penalty for premiums, including the following:

• Medicare Part A premium penalty — The penalty is a 10% monthly increase if you have to pay a Part A premium. You will be charged for twice the number of years you delay enrollment.
• Medicare Part B premium penalty — The Part B premium penalty is 10% for each 12-month period you delay enrollment. In most instances, you would have to pay the penalty each month as long as you have Part B. 
• Medicare Part D premium penalty — For each month you delay enrollment, the penalty is 1% of the average Part D premium. The penalty must be paid for as long as you are enrolled in Part D. 

To avoid incurring a Medicare penalty, it’s crucial that you enroll during your Initial Enrollment Period once you are eligible to do so. 

Contact an Experienced Elder Law Attorney

If you’re unclear about your Medicare enrollment options or require assistance with navigating the enrollment process, Estate Planning & Elder Law Services in Michigan can help. We can connect you with trusted professionals who can provide the guidance you need. Contact us today to schedule a consultation to learn about the services we offer.