OEP vs AEP: Complete Guide to Medicare Enrollment Periods 2026
Medicare has two key enrollment windows: Annual Enrollment Period (AEP) runs October 15–December 7, and Open Enrollment Period (OEP) runs January 1–March 31. AEP is for everyone with Medicare; OEP is only for people who already have Medicare Advantage or Part D. Understanding the difference helps you make changes at the right time.
Quick comparison
- AEP: Oct 15–Dec 7; everyone with Medicare; changes effective Jan 1.
- OEP: Jan 1–Mar 31; Advantage/Part D members only; changes effective first of next month.
For a full breakdown of who qualifies, what changes you can make in each period, and Vancouver/Clark County resources, see Understanding Medicare Open Enrollment Period (OEP) 2026.
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Disclaimers
American Senior Choices is not affiliated with or endorsed by the U.S. government or the federal Medicare program. We do not offer every plan available in your area. Any information provided is limited to the plans we do offer. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Program to get information on all your options.