The short answer
The fall and winter bring several overlapping enrollment periods that are easy to confuse. The Medicare Annual Enrollment Period, or AEP, runs in the fall and lets people with Medicare change their Advantage or Part D plans. The ACA Open Enrollment Period, for people buying individual health coverage under 65, runs in the fall and winter. And the Medicare Advantage Open Enrollment Period, or OEP, comes in the new year, letting Advantage enrollees make one change. Knowing which period applies to you, and its dates, ensures you act in the right window.
So AEP is for Medicare changes in the fall, ACA Open Enrollment is for individual coverage, and the Medicare Advantage OEP comes in the new year.
Which period is which
The Medicare AEP each fall is when people with Medicare can join, switch, or drop Advantage and Part D plans for coverage starting January 1. ACA Open Enrollment, overlapping in the fall and winter, is when people under 65 enroll in or change individual Marketplace plans. The Medicare Advantage OEP early in the new year gives those already in an Advantage plan a one-time chance to switch to another Advantage plan or return to Original Medicare. Our guide to AEP vs. the Medicare Advantage OEP covers the Medicare distinction, and our open enrollment page covers the calendar.
Each period serves a different group — Medicare beneficiaries, individual-market buyers, or existing Advantage members — at a different time.
How to use the calendar
Identify which coverage you have and therefore which enrollment period applies, note its dates, and make any changes within that window so your coverage takes effect on time. Because the periods overlap and have different rules, confusing them can cause missed deadlines. A local licensed advisor can help you act in the right window at no cost. Our open enrollment page covers the details. This is educational information.
The takeaway: the fall and winter hold overlapping enrollment periods — Medicare AEP, ACA Open Enrollment, and the Medicare Advantage OEP — so know which applies to you and its dates.
Frequently Asked Questions
What is the difference between AEP, OEP, and ACA Open Enrollment?
AEP is the Medicare fall period to change Advantage or Part D plans; ACA Open Enrollment is for individual coverage under 65; and the Medicare Advantage OEP in the new year lets Advantage enrollees make one change.
When is Medicare Annual Enrollment?
The Medicare AEP runs in the fall, when people with Medicare can join, switch, or drop Advantage and Part D plans for coverage starting January 1.
Which enrollment period applies to me?
It depends on your coverage — Medicare beneficiaries use AEP and possibly the Advantage OEP, while people under 65 buying individual coverage use ACA Open Enrollment. Confirm the dates for your situation.
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