Annual Enrollment Period (AEP) runs October 15 through December 7 each year. For most people, a plan choice received by December 7 takes effect January 1, 2027. This is the main window to change Medicare Advantage (Part C) and stand-alone Part D drug plans for the upcoming contract year.
What you can do during AEP
- Join a Medicare Advantage plan if you are eligible
- Switch from one Advantage plan to another
- Drop Advantage and return to Original Medicare (Parts A and B)
- Change Part D plans—or add Part D if you use Original Medicare and need drug coverage
- Move between Advantage with drug coverage (MAPD) and Advantage without drug coverage, when plans are available in your area
Doing nothing is also a choice: if your current plan continues in your county, you usually stay enrolled under the plan’s 2027 terms unless you actively switch.
What AEP does not automatically cover
Medicare Supplement (Medigap) is not governed by this same federal window. If you leave Advantage for Original Medicare and want a supplement, you may need to pass medical underwriting unless you qualify for a guaranteed-issue right (for example, after certain plan exits). State rules in Idaho, Oregon, Texas, and Washington differ—confirm timing before you cancel Advantage coverage.
For the difference between a routine Annual Notice of Change and a true plan exit, see ANOC vs. non-renewal and Medigap rights. For state birthday rules that are separate from AEP, see Oregon and Idaho Medigap birthday windows.
Practical steps before December 7
- Read your Annual Notice of Change if you are in Advantage or Part D.
- Update your medication list and confirm doctors in Plan Finder after October directory refreshes.
- Compare total cost—premium, deductibles, copays, and drug tiers—not premium alone.
- Enroll through Medicare.gov, the plan, or an agent; keep confirmation numbers.
Questions about switching for 2027?
CDA Insurance can review Advantage, Part D, and Medigap paths with you for Idaho, Oregon, Texas, and Washington.
This article is for general education. It is not a plan recommendation, quote, or guarantee of coverage. Benefits, premiums, networks, and eligibility vary by plan and county and can change. CDA Insurance LLC is an independent insurance agency and is not connected with the U.S. government or the federal Medicare program. Official program information is available at Medicare.gov or 1-800-MEDICARE.