This content is for general informational purposes and does not constitute medical, legal, or financial advice. Healthcare rules and costs change annually. Last reviewed: January 15, 2025. Always verify current details with your insurer, employer, or a licensed healthcare navigator.
Annual Enrollment Period (Medicare)
The October 15–December 7 window when Medicare beneficiaries can change their coverage.
Full Definition
The Annual Enrollment Period (AEP) for Medicare runs from October 15 through December 7 each year. During this period, Medicare beneficiaries can switch from Original Medicare to Medicare Advantage (or vice versa), change Medicare Advantage plans, and join, drop, or switch Medicare Part D drug plans. Changes made during AEP take effect January 1 of the following year. This is distinct from the Medicare Advantage Open Enrollment Period (January 1–March 31), which has more limited options.
Real-World Example
In November, you review your Medicare Advantage plan's updated formulary and notice your cholesterol medication moved to a more expensive tier. During AEP, you switch to a different Part D plan that covers your drug at a lower cost — taking effect January 1.
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