The Medicare Annual Enrollment Period (AEP) represents a yearly window for millions of Medicare beneficiaries to review and potentially change their health and prescription drug coverage. The choices made during this time determine a beneficiary’s medical and financial coverage for the entire following year. Since private Medicare plans, such as Medicare Advantage and Part D, frequently adjust their benefits, costs, and networks, the AEP provides a mechanism for people to ensure their coverage meets their evolving health needs and budget.
Defining the Annual Enrollment Period
The Annual Enrollment Period is a specific, seven-week timeframe that occurs every fall for all existing Medicare beneficiaries. This period begins on October 15th and concludes on December 7th each year. This window allows beneficiaries to make changes to coverage options provided by private insurance companies, such as Medicare Advantage (Part C) and Part D prescription drug plans.
Private plans offering Part C and Part D coverage are permitted to make significant changes to their structure, including premiums, deductibles, and drug formularies, for the upcoming calendar year. Any enrollment choices or changes made during the AEP become effective on January 1st of the subsequent year. Beneficiaries satisfied with their current plan do not need to take any action; their existing coverage will simply renew, provided the plan is still offered.
Enrollment Actions Permitted
The AEP is the most comprehensive enrollment period available to Medicare beneficiaries, allowing for a wide array of coverage changes.
Switching Between Original Medicare and Medicare Advantage
Individuals enrolled in Original Medicare (Parts A and B) can switch to a Medicare Advantage Plan (Part C), which bundles hospital, medical, and often drug coverage. Conversely, those currently enrolled in a Medicare Advantage Plan can drop it and return to Original Medicare. A beneficiary can also switch from one Medicare Advantage Plan to a different Medicare Advantage Plan.
Prescription Drug Coverage (Part D)
For prescription drug coverage, AEP allows beneficiaries to enroll in a stand-alone Medicare Prescription Drug Plan (Part D) for the first time. Those already with Part D coverage can switch to a different Part D plan, or they may choose to drop their Part D coverage entirely. Dropping coverage may lead to a late enrollment penalty if they re-enroll later. All changes submitted during this period will take effect simultaneously on January 1st.
Key Differences from Other Enrollment Periods
The AEP is distinct from the Medicare Advantage Open Enrollment Period (OEP) and Special Enrollment Periods (SEP) primarily due to its scope. The AEP is open to all Medicare beneficiaries and permits the most significant changes, including adding or dropping Part D coverage and freely moving between Original Medicare and Medicare Advantage.
Medicare Advantage Open Enrollment Period (OEP)
The Medicare Advantage OEP runs from January 1st through March 31st and is solely for individuals already enrolled in a Medicare Advantage Plan. During the OEP, an individual can make a single change: switch to a different Medicare Advantage Plan or drop the plan and return to Original Medicare. If returning to Original Medicare, they can also enroll in a stand-alone Part D plan.
Special Enrollment Periods (SEPs)
SEPs are triggered by specific life events that occur outside of the standard enrollment windows. These events can include moving outside the plan’s service area, losing other creditable coverage, or qualifying for Extra Help with prescription drug costs. SEPs allow beneficiaries to change plans immediately following the qualifying event, unlike the AEP, which has a set effective date of January 1st.
Preparing for Enrollment Decisions
Effective preparation for the AEP should begin well before the October 15th start date. Medicare Advantage and Part D plans are required to send an Annual Notice of Change (ANOC) document to current enrollees by the end of September. This document summarizes all changes to the plan’s costs, coverage, and benefits that will take effect on January 1st.
Beneficiaries should thoroughly review their ANOC to identify changes in premiums, deductibles, or co-payments. They must also check for changes to the plan’s drug formulary (the official list of covered medications) to ensure current prescriptions are still covered and at what cost tier. Changes to the provider and pharmacy networks are also listed, confirming that preferred doctors and hospitals remain in-network.
After reviewing their current plan’s changes, beneficiaries can use official resources like the Medicare Plan Finder tool to compare all available plans in their area. This research ensures the final enrollment decision during the AEP is a deliberate choice based on next year’s specific financial and health needs.