There are several times throughout the year when Medicare beneficiaries can enroll in a plan or make changes to their Medicare coverage, depending on their individual circumstances. For beneficiaries that are currently enrolled in either Original Medicare Part A and Part B or a Part C Medicare Advantage (MA) plan, two important Medicare enrollment periods are the Annual Enrollment Period and the Open Enrollment Period.

While sometimes OEP and AEP are used to refer to the same enrollment period, there is also the Medicare Advantage Open Enrollment Period that has different rules. Read on to learn more about the similarities and differences between OEP and AEP and how to enroll in a Medicare plan.

What is the Medicare Annual Enrollment Period?

The Medicare Annual Enrollment Period (AEP), also called the Medicare Annual Election Period (AEP) and Medicare Open Enrollment Period (OEP), happens each year from October 15 through December 7. During this time, beneficiaries are able to make changes to their current Medicare coverage.

Any plan and benefit changes become effective on January 1 the following year.

On October 1 each year, to prepare for Medicare AEP, health insurance companies release information about their plan benefits for the following year. Examples of information shared can include covered benefits, premium changes, prescription drug coverage updates, and more.

What changes can you make during AEP?

There may be dozens of different Medicare Advantage plans available for you to choose from depending on where you live and your needs. During AEP, you can make changes to your Medicare Advantage plans and Medicare Part D prescription drug plans. Examples of changes you can make include moving from Original Medicare to a Medicare Advantage plan or dropping your MA plan and returning to Original Medicare.

You can also enroll in a different MA plan, choose a new Medicare Part D plan, or add a Part D plan if you don’t have one. You can also cancel your Part D plan, but if you don’t maintain credible drug coverage and decide to re-enroll in a Part D plan later, you’ll have to pay a late enrollment penalty.

This enrollment period doesn’t apply to Medicare Supplement (Medigap) plans. If you change your Medigap plan during this time, the same rules apply as they would at any other time during the year.

What is the Medicare Open Enrollment Period?

The Medicare Open Enrollment Period (OEP) can mean different things. Again, it is often used interchangeably with AEP, October 15 through December 7.

However, there is also a Medicare Advantage Open Enrollment Period (MA OEP). This enrollment period takes place January 1 through March 31. Your new coverage will begin the first of the following month. For example, if you enroll on January 15, your coverage will begin February 1. If you enroll February 10, your coverage will begin March 1.

What changes can you make during OEP?

If referring to OEP as the same period as AEP, you can make the same changes stated above.

If referring to the MA OEP, you can only make changes to your current Medicare Advantage coverage. For example, you can switch to a different MA plan or drop your MA coverage and return to Original Medicare. If you return to Original Medicare, you are also able to add a Part D plan at this time.

You can compare Medicare plans quickly and easily with our Find a Plan tool. Just enter your zip code to review the costs and benefits of Medicare plans in your area.

OEP vs. AEP

As stated, OEP and AEP are sometimes referring to the same time period when beneficiaries can make changes to their MA or Part D coverage from October 15 through December 7. During AEP, beneficiaries have more options and flexibility with their plan enrollment. Additionally, beneficiaries can make multiple changes and updates during this time, including enrolling in a plan, changing their mind, and enrolling in a different plan, as long as it all happens before December 7.

However, MA OEP is a different time where only beneficiaries currently enrolled in an MA plan can make changes to their coverage. There is less flexibility during this time, especially because you can only make one change in plan coverage.

Should I enroll during OEP or AEP?

If you are enrolled in Original Medicare and want to enroll in a Medicare Advantage plan, you must make this change during AEP.

If you are already enrolled in an MA plan and want to change to a different MA plan or return to Original Medicare (and enroll in a standalone Part D plan), you can do this during AEP or MA OEP.

How do you make changes to your Medicare plan?

If you are switching or enrolling in a plan during AEP, join your new plan by contacting the plan directly by phone, filling out an enrollment form online, or submitting a paper enrollment form through the mail. You will automatically be disenrolled from your current plan on December 31, and your new coverage will begin January 1.

If you are switching plans during the MA OEP, you’ll take the same steps to enroll in your new plan. Then, contact your current plan to learn how to disenroll from your current coverage. Your new plan coverage will begin on the first of the following month.

If you would like to return to Original Medicare, visit Medicare.gov to enroll online or call 1-800-633-4227 (TTY 1-877-486-2048).

Can I make changes to my Medicare plan during other times?

If you don’t make any changes during MA OEP or AEP, you will have to keep your current plan until the next AEP or MA OEP the following year.

Or, you can make changes if you qualify for a Special Enrollment Period (SEP). You may qualify if you move to a new address that isn’t in your current plan’s service area or you have new plan options, you lose your current coverage, your plan changes its contract with Medicare, or other special situations.

If you qualify for an SEP, you can make changes to your MA plan and/or drug coverage. And if you have any questions about Medicare or the plans available to you, give us a call. One of our licensed agents will answer your questions and explain your options to help you find the right Medicare coverage for your unique needs.

Additional resources

• ClearMatch Medicare: Find a Medicare Plan
• Medicare.gov: Medicare Costs