Enrollment
Medicare Advantage Open Enrollment Period (OEP)
Quick answer
The Medicare Advantage Open Enrollment Period (OEP) runs January 1 – March 31. If you're already in a Medicare Advantage plan, you can switch to a different MA plan once or go back to Original Medicare (and add a PDP).
Plain-English definition
OEP is for MA members only. It is not a general re-enrollment window.
Why it matters
OEP gives you a do-over if your AEP choice isn't working out.
A simple example
You joined a new MA plan January 1 and realized your doctor isn't in network. You use OEP in February to switch.
Common mistakes & misconceptions
Related terms
Annual Election Period (AEP)
The Annual Election Period (AEP) runs October 15 – December 7 each year. During AEP anyone with Medicare can join, switch, or drop a Medicare Advantage or Part D plan. Changes take effect January 1.
Medicare Advantage (Part C)
Medicare Advantage, also called Part C, is a way to receive your Medicare benefits through a private insurance plan approved by Medicare. Plans bundle Part A and Part B, usually include Part D drug coverage, and often add dental, vision, and hearing.
Special Enrollment Period (SEP)
A Special Enrollment Period (SEP) is a window outside the standard windows when you can join, switch, or drop a plan. SEPs are triggered by qualifying life events like moving, losing employer coverage, or becoming eligible for Medicaid.
Frequently asked questions
Can I use OEP to join an MA plan for the first time?+
No — OEP is for people already in an MA plan.
Sources & references
📚 Where this information comes from
- Medicare.gov — official U.S. government site for people with Medicare ↗Primary source for benefits, enrollment periods, and plan comparison.
- CMS.gov — Centers for Medicare & Medicaid Services ↗Federal rulemaking, program updates, and official guidance.
- Social Security Administration — Medicare enrollment & premiums ↗Enrollment, premium withholding, and IRMAA determinations.
When you're ready, compare plans on your own terms
See Medicare Advantage plans from the insurance companies we represent, or walk the course with a licensed agent whenever you'd like a second set of eyes.
We help compare Medicare Advantage plans from the insurance companies we represent, and we don't offer every plan available in your area.
Medicare Caddies is an independent insurance agency. We are not affiliated with, endorsed by, or connected to the U.S. government, the federal Medicare program, or the Centers for Medicare & Medicaid Services (CMS). We help compare Medicare Advantage plans from the insurance companies we represent, and we don't offer every plan available in your area.