Part D enrollment periods explained

Initial Enrollment Period (IEP)

Your IEP is a 7-month window when you first become eligible for Medicare. For most people, this is around their 65th birthday:

• Starts: 3 months before your 65th birthday month
• Includes: Your birthday month
• Ends: 3 months after your birthday month

This is the most important enrollment window. Missing it without creditable coverage triggers the permanent late enrollment penalty.

Annual Election Period (AEP)

October 15 – December 7 each year. During this time, any Medicare beneficiary can:

• Join a Part D plan
• Switch from one Part D plan to another
• Drop Part D coverage

Coverage changes made during AEP take effect on January 1 of the following year.

Open Enrollment Period (OEP)

January 1 – March 31 each year. If you're in a Medicare Advantage plan, you can:

• Switch to a different Medicare Advantage plan (with or without drug coverage)
• Drop your Medicare Advantage plan and return to Original Medicare (and enroll in a standalone Part D plan)

Note: This period does not allow switching between standalone Part D plans.

Special Enrollment Periods (SEPs)

Certain qualifying life events allow you to enroll in, switch, or drop a Medicare Part D or Medicare Advantage plan outside the regular enrollment windows. Here are the most common SEPs:

Change in residence

• You permanently move to a new area where your current plan isn't available
• You move into or out of a plan's service area
• You are released from incarceration

Coverage typically begins the first of the month after you make your election. You generally have up to 2 months after the move to enroll.

Loss of creditable coverage

• You involuntarily lose creditable drug coverage (e.g., employer plan terminates, coverage is reduced below creditable status)
• Your employer group health plan (including COBRA, retiree, or commercial coverage) ends
• Your current plan leaves Medicare or reduces its service area

This does not include losing coverage due to nonpayment of premiums. You generally have 2 months from the date of the coverage loss to enroll.

Change in employer group health plan

• You lose employer or union drug coverage (voluntary or involuntary termination of group coverage)
• You gain employer group health plan coverage and want to disenroll from your current plan
• Your employer plan changes and you need to adjust your Medicare coverage

Medicaid and dual eligibility changes

• You gain or lose Medicaid eligibility
• You become eligible for or lose eligibility for a Medicare Savings Program
• You qualify for a Dual Eligible Special Needs Plan (D-SNP)
• If you have both Medicare and Medicaid, you can switch plans once per month

Extra Help (Low-Income Subsidy)

• You qualify for Extra Help for the first time
• You lose Extra Help eligibility
• Your level of Extra Help changes (e.g., copay amount changes)
• If you receive Extra Help, you have a continuous SEP allowing you to change plans once per calendar quarter (January through September)

Entering or leaving an institution

• You enter or leave a nursing home, skilled nursing facility, long-term care facility, or similar institution

Plan performance and contract issues

• Your plan receives a 5-star quality rating from Medicare — you can switch to that plan at any time during the year
• Your plan violated its contract or provided misleading information
• CMS or your state takes an enforcement action against your plan

Other qualifying events

• You are affected by a FEMA-declared disaster or other emergency
• You disenrolled from a plan due to erroneous information or a plan error
• You were enrolled in a plan by a third party without your consent
• You have a chronic health condition that qualifies you for a Chronic Condition Special Needs Plan (C-SNP)
• You dropped a Medigap policy to join a Medicare Advantage plan for the first time and want to return to Original Medicare within 12 months