The Medicare Annual Enrollment Period (AEP) runs from October 15 through December 7 every year. During this window, beneficiaries have more flexibility to change their coverage than at virtually any other time. But there's widespread confusion about what's actually allowed — and the stakes are high, because your choices take effect January 1 and generally lock you in for the full year.
What You CAN Change During AEP
- Switch from Original Medicare (Parts A and B) to a Medicare Advantage plan
- Switch from Medicare Advantage back to Original Medicare
- Switch from one Medicare Advantage plan to a different one
- Join, switch, or drop a Part D prescription drug plan
What You CANNOT Do During AEP
Here's where most people are surprised: the Annual Enrollment Period does not let you enroll in a Medicare Supplement (Medigap) plan without medical underwriting — unless you have a guaranteed issue right. Medigap has its own enrollment rules and is governed separately from Medicare Advantage and Part D.
If you want to switch from Medicare Advantage to a Medigap plan, you'll typically need to qualify medically. The exception is during the Medicare Advantage Open Enrollment Period (January 1 – March 31), where in some states you may have additional rights.
The Medicare Advantage Open Enrollment Period (MA OEP)
There's a second window — the MA OEP — that runs January 1 through March 31. If you're already enrolled in a Medicare Advantage plan, you can use this period to switch to a different MA plan or return to Original Medicare and join a Part D plan. However, you cannot use the MA OEP to switch from Original Medicare into Medicare Advantage — that only happens during AEP or with a qualifying Special Enrollment Period.
Why Plans Change Every Year
Every Medicare Advantage and Part D plan files its rates, formulary, and benefits with CMS annually. That means the plan you enrolled in this year may have different premiums, copays, deductibles, covered drugs, and network providers next year. A plan that was ideal in 2022 may have changed significantly by 2023.
This is why an annual review — every fall, before the AEP closes — is not just a nice-to-have. It's essential. At Insurance Innovators LLC, we conduct those reviews at no charge for beneficiaries across 38 states. If your current plan is still your best option, we'll tell you that honestly. If something better is available, we'll walk you through it.
What to Bring to Your Review
- Your current Medicare card and plan ID card
- A list of your prescriptions (name, dosage, frequency)
- Names of your doctors and any specialists you see regularly
- Your preferred pharmacy
Ready to review your coverage? Call us at (530) 395-5309 or use the contact form on this site. We'll take it from there.