Medicare Advantage Open Enrollment Period

If you’re already enrolled in a Medicare Advantage (MA) plan, the Medicare Advantage Open Enrollment Period (MA OEP) is a once-a-year chance to make a change to your coverage. During this window, you can switch to a different Medicare Advantage plan or leave Medicare Advantage and return to Original Medicare. Because specific rules apply—and you’re limited to one change—it helps to understand exactly what this period allows.

Key takeaways

  • MA OEP dates: January 1 through March 31 each year

  • Who can use it: People who are enrolled in a Medicare Advantage plan as of January 1

  • What you can do:

    • Switch to another Medicare Advantage plan (with or without drug coverage), or

    • Return to Original Medicare and, if needed, add a Part D prescription drug plan

  • How many changes: One change during the MA OEP

  • When changes start: The first day of the month after your enrollment request is received

What is the Medicare Advantage Open Enrollment Period?

The MA OEP is designed for people who already have Medicare Advantage and want to adjust their coverage after the year begins. It runs from January 1 to March 31 and occurs only once per year.

Who can participate?

You can use the MA OEP if you are already enrolled in a Medicare Advantage plan on January 1. If you’re in Original Medicare (and not currently in MA), this period generally doesn’t apply to you.

What changes can you make during MA OEP?

During MA OEP, you can make one of the following changes:

  1. Switch Medicare Advantage plans
    You can move from your current MA plan to another MA plan, whether it includes prescription drug coverage or not.

  2. Return to Original Medicare
    You can disenroll from Medicare Advantage and go back to Original Medicare. If you want prescription coverage, you can also enroll in a Part D plan at that time.

When does your new coverage begin?

Once your request is received, the change typically takes effect on the first day of the next month.

Can you change your plan after MA OEP ends?

Yes—sometimes. If you have a qualifying event, you may be able to make changes during a Special Enrollment Period (SEP). Examples include:

  • moving outside your plan’s service area,

  • losing other insurance coverage, or

  • your plan ending or not renewing its contract.

Depending on the situation, SEPs often give you about 30 to 60 days to make a change.

When can you disenroll from Medicare Advantage?

In most cases, you can leave a Medicare Advantage plan during:

  • MA OEP (Jan. 1–Mar. 31)

  • Annual Enrollment Period (AEP) (Oct. 15–Dec. 7)

  • an SEP, if you qualify

How is MA OEP different from the Annual Enrollment Period (AEP)?

These periods serve different purposes:

  • MA OEP (Jan. 1–Mar. 31):
    Only for people already in Medicare Advantage on January 1; one change allowed.

  • AEP (Oct. 15–Dec. 7):
    Open to most Medicare-eligible individuals; you can make multiple changes, and coverage starts January 1.

Bottom line

The Medicare Advantage Open Enrollment Period gives current MA members a limited, once-a-year opportunity to make one change—either switch to another Medicare Advantage plan or return to Original Medicare—so your coverage better fits your needs.