Medicare AEP vs. OEP: Which Enrollment Period Applies to You?

AEP: October 15 through December 7

During AEP, eligible Medicare beneficiaries can review their coverage for the coming year. For the current fall season, a valid request received by the plan by December 7, 2026 takes effect January 1, 2027.

• Switch from Original Medicare to a Medicare Advantage plan, if eligible.
• Switch from one Medicare Advantage plan to another, with or without prescription drug coverage.
• Leave Medicare Advantage and return to Original Medicare, with the option to join a separate Part D drug plan.
• Join, switch, or drop a standalone Part D plan while on Original Medicare.

You can make more than one election during AEP; the last valid election received by the deadline generally takes effect. Keep your confirmation and verify which plan will start in January.

Medicare Advantage OEP: January 1 through March 31

This annual window is for people already enrolled in Medicare Advantage. It allows one change: switch to another Medicare Advantage plan, with or without drug coverage, or return to Original Medicare with the opportunity to join a separate Part D plan.

The change starts the first day of the month after the plan receives your request. For example, an eligible switch requested in February 2027 starts March 1, 2027.

• OEP alone does not let someone on Original Medicare join Medicare Advantage.
• OEP alone does not let someone change standalone Part D plans while remaining on Original Medicare.
• After using the one OEP change, another change requires a separate applicable enrollment opportunity.

Do not confuse these windows with first-time Medicare enrollment

AEP and Medicare Advantage OEP are not the usual windows for first signing up for Medicare Parts A and B. New Medicare beneficiaries have their own initial enrollment rules. People who enroll in Medicare Advantage when first getting Medicare also have an individual opportunity to change coverage during their first three months with both Parts A and B.

Certain life events, such as a qualifying move or loss of coverage, may create a Special Enrollment Period. Eligibility, deadlines, and effective dates depend on the specific situation.

Medicare Supplement has separate rules

Returning to Original Medicare does not automatically guarantee that you can buy a Medicare Supplement, also called Medigap. Outside your Medigap Open Enrollment Period or another protected right, an insurer may use medical underwriting and may decline an application.

Before leaving Medicare Advantage expecting to add Medigap, verify acceptance, price, effective dates, and prescription coverage. A quote is not confirmation that a supplement has been issued.

Prepare for a useful coverage conversation

• Gather your current plan name and Annual Notice of Change.
• List your doctors, hospitals, medications, dosages, and preferred pharmacy.
• Think about the care you expect to use and the costs you can comfortably manage.
• Ask which enrollment period applies and request confirmation of the coverage start date.

A review does not mean you have to switch. If your plan continues and still meets your needs, keeping it may be appropriate.

Clear dates. Personal guidance. No obligation.

Call Laurie Pusztai and Samson Lewis at 888-751-3421 for complimentary Medicare education and guidance. We will help you understand the questions to ask and the enrollment timing that applies to your situation. There is no obligation to enroll.

Call 888-751-3421

Request a Medicare guidance appointment

Learn what to do with your ANOC