Medicare Advantage Open Enrollment runs from January 1 through March 31. If you are already in Medicare Advantage, it lets you make one plan change. It is separate from fall Medicare Open Enrollment. You cannot use this period to join or leave a Medicare Medical Savings Account (MSA) plan.

If you joined Medicare Advantage during your Initial Enrollment Period, you have another opportunity to change. During your first three months with both Part A and Part B, you can switch to another Advantage plan or return to Original Medicare, adding drug coverage if needed. This is distinct from the recurring January–March period. Medicare explains both opportunities.

What Changes Can You Make?

If you are already enrolled in Medicare Advantage, you can make one of these changes:

  • Switch to another Medicare Advantage plan, with or without drug coverage
  • Drop Medicare Advantage and return to Original Medicare
  • Join a stand-alone Part D plan when returning to Original Medicare

The change generally takes effect on the first day of the month after the new plan receives your request.

What Can You Not Do?

During this January 1–March 31 period, someone in Original Medicare cannot use it to join Medicare Advantage, add a Part D plan, or switch from one stand-alone drug plan to another.

If you return to Original Medicare, you are not always guaranteed a Medigap policy. Federal rules give you a right to buy certain policies only in specific situations, and state protections vary.

Review the Full Consequences

Before changing, verify your doctors, prescriptions, pharmacies, expected costs, and requirements for approval before care, called prior authorization. If moving to Original Medicare, arrange drug coverage and explore Medigap before the Advantage plan ends.

If a permitted request is received in February, the change generally starts March 1. When returning to Original Medicare, confirm the Part D start date and any Medigap acceptance before that date.

Medicare policy sources last checked: October 8, 2026.