Medicare Annual Enrollment Period: Your Complete Guide
The Annual Enrollment Period from October 15 to December 7 is your primary opportunity to review and change your Medicare coverage for the coming year.
When Is the Annual Enrollment Period?
The Medicare Annual Enrollment Period (AEP) runs from October 15 through December 7 every year. Any changes you make during this period take effect on January 1 of the following year.
This is the most important enrollment window for Medicare beneficiaries because it is the primary time to review your current coverage and make changes. Even if you are happy with your current plan, reviewing your options each year is essential because plan benefits, premiums, provider networks, and drug formularies change annually.
Plan information for the coming year is released on October 1, giving you two weeks to review details before the enrollment window opens on October 15.
What Changes Can You Make During AEP?
During the Annual Enrollment Period, you can make the following changes:
Switch from Original Medicare to a Medicare Advantage plan. This allows you to join an all-in-one plan that bundles your Part A, Part B, and usually Part D benefits.
Switch from a Medicare Advantage plan back to Original Medicare. If you are unhappy with your MA plan, you can return to Original Medicare and join a stand-alone Part D plan.
Switch from one Medicare Advantage plan to a different Medicare Advantage plan. You can change to a different plan type, carrier, or benefit structure.
Join a Medicare Part D prescription drug plan. If you currently have Original Medicare without Part D, you can add drug coverage.
Switch from one Part D plan to another. If your current plan's formulary no longer covers your drugs or costs have increased, you can change plans.
Drop your Part D plan. Though not generally recommended due to late enrollment penalty implications if you lack other creditable drug coverage.
How to Prepare for AEP
Starting in September, take these steps to prepare for a productive enrollment period:
Review your Annual Notice of Change (ANOC): Your current plan sends this document by September 30 each year. It details all changes to your plan for the coming year, including premium changes, benefit modifications, formulary updates, and network changes.
List your current medications: Create a complete list of every prescription you take, including drug name, dosage, and quantity. You will need this to compare Part D formularies.
Identify your preferred providers: Note which doctors, specialists, and hospitals you want to continue using. Check whether they will remain in-network for any plans you are considering.
Assess your past year's healthcare use: Review how much you spent on healthcare, what services you used, and whether your current plan met your needs.
Set a budget: Determine what you can afford in monthly premiums and estimate your expected out-of-pocket costs based on anticipated healthcare use.
Comparing Plans During AEP
Use the Medicare Plan Finder at Medicare.gov to compare plans available in your area. The tool allows you to enter your medications, preferred providers, and preferences to see personalized cost estimates.
When comparing plans, focus on total estimated annual cost (not just premiums), whether your doctors are in the plan's network, whether your prescriptions are on the plan's formulary and at what tier, the plan's star rating for quality, the out-of-pocket maximum for Medicare Advantage plans, and any extra benefits like dental, vision, hearing, and fitness programs.
Do not assume your current plan is still the best option. Plans change significantly from year to year, and a plan that was ideal last year may no longer be the best choice. Even a few minutes of comparison shopping can save hundreds of dollars.
Common AEP Mistakes to Avoid
Not reviewing your plan annually: Even satisfied members should check because plan costs, formularies, and networks change. Your drugs could move to a higher cost tier or your doctor could leave the network.
Focusing only on premiums: A $0 premium plan may cost more overall if it has higher copays, a larger deductible, or does not cover your medications well.
Not checking your drug formulary: Formularies change every year. A drug covered this year might require prior authorization, move to a higher tier, or be dropped entirely next year.
Waiting until the last day: Enrolling early avoids the stress of the December 7 deadline and ensures your enrollment is processed correctly.
Not considering Medigap timing: If you are thinking about switching from Medicare Advantage to Original Medicare with Medigap, remember that Medigap enrollment outside your initial open enrollment period may require medical underwriting. Some states offer guaranteed issue rights when leaving MA plans.
Frequently Asked Questions
When is the Medicare Annual Enrollment Period?
The Annual Enrollment Period runs from October 15 through December 7 each year. Changes made during this period take effect on January 1 of the following year.
Do I have to change my Medicare plan during AEP?
No. If you are satisfied with your current Medicare coverage, you do not need to make any changes. Your plan will continue automatically. However, it is strongly recommended to review your plan annually since benefits, costs, and networks change each year.
What happens if I miss the Annual Enrollment Period?
If you miss the AEP, you generally must wait until the next Annual Enrollment Period to make changes, unless you qualify for a Special Enrollment Period due to a qualifying life event. If you are in a Medicare Advantage plan, you can make one change during the MA Open Enrollment Period (January 1 - March 31).
Can I go from Medicare Advantage back to Original Medicare during AEP?
Yes. During the Annual Enrollment Period (October 15 - December 7), you can disenroll from your Medicare Advantage plan and return to Original Medicare. You can also join a stand-alone Part D plan at the same time. The change takes effect January 1.
Related Guides
What Is Medicare Advantage (Part C)?
Medicare Advantage plans are an alternative way to get your Medicare coverage through private insurance companies approved by Medicare.
Medicare Advantage vs. Original Medicare: A Side-by-Side Comparison
Choosing between Medicare Advantage and Original Medicare is one of the most important decisions you will make when you become eligible for Medicare.
When to Enroll in Medicare: Key Enrollment Periods
Understanding Medicare enrollment periods is critical to getting coverage when you need it and avoiding costly late enrollment penalties.
Understanding Medicare Part D Prescription Drug Plans
Medicare Part D provides prescription drug coverage through private insurance plans, either as a stand-alone plan or included in a Medicare Advantage plan.
Disclaimer: Plan availability, benefits, and premiums vary by location. Contact Medicare.gov or 1-800-MEDICARE for complete information. We do not offer every plan available in your area. Any information we provide is limited to those plans we do offer in your area. Please contact Medicare.gov or 1-800-MEDICARE to get information on all of your options.