Medicare & ACA Enrollment Windows

Choosing coverage is only possible during certain enrollment windows. Missing them can mean waiting — or paying a penalty.

At a glance

Original Medicare — Initial Enrollment Period (IEP)

Everyone aging in has a 7-month IEP to enroll in Parts A and B without penalty: the 3 months before the month they turn 65, the birthday month, and the 3 months after. Delaying Part B can delay other windows (like the ICEP and Medigap OEP) and may cause penalties.

Medicare Advantage — when you can enroll

Initial Coverage Election Period (ICEP)

The first time a person can join an MA plan. They must have Parts A and B first. It lasts 7 months and usually runs alongside the IEP. If Part B is delayed, the ICEP starts 3 months before the Part B effective month and ends 3 months after Part B begins.

Annual Enrollment Period (AEP) — Oct 15 to Dec 7

The same dates every year. Beneficiaries can join, switch, or drop an MA plan or a Part D plan. Coverage chosen here takes effect January 1. This is the busiest enrollment season.

MA Open Enrollment Period (MA OEP) — Jan 1 to Mar 31

For people already in an MA plan as of January 1. They may switch to a different MA plan or return to Original Medicare (and then add a stand-alone Part D plan, and possibly a Medigap plan). New-to-Medicare people who joined an MA plan during their ICEP also get this window early in their entitlement. (Agents shouldn't market the MA OEP as an open sales window, but may help clients who are unhappy with their choice.)

Special Enrollment Periods (SEPs)

Qualifying life events — losing coverage, moving, losing income, becoming institutionalized, gaining Medicaid, a new chronic condition, etc. — can open an SEP to enroll in or leave an MA plan. Each SEP has its own timing and allowed changes, and SEPs must be used appropriately for the person's actual situation.

The MA "Trial Right" SEP

Someone who joins an MA plan when first eligible at 65 gets a 12-month trial: they may disenroll and return to Original Medicare, with a guaranteed-issue right to buy a Medigap plan lasting 63 days after disenrolling (and a Part D SEP if they had an MAPD plan).

Part D — Prescription Drugs

Part D follows the same major windows: the IEP around 65, the AEP (Oct 15–Dec 7) to join/switch/drop, the MA OEP to pick up a stand-alone plan when leaving MA, and SEPs for qualifying events. Going without creditable drug coverage can trigger a late-enrollment penalty (see Part D Prescription Drug Coverage).

Medigap (Medicare Supplement) — different rules

Medigap is not tied to AEP. The ideal window is the 6-month Medigap Open Enrollment Period (OEP), which begins the first month a person has Part B and is 65 or older. During it, you have a guaranteed-issue right — any plan, any participating carrier, regardless of health.

Outside the OEP you can apply year-round, but unless you have a guaranteed-issue right (see Medicare Supplement (Medigap) Plans & Underwriting) or a trial right, you'll typically have to pass medical underwriting. To return from an MA plan to Original Medicare with a Medigap policy, a person generally waits until the Medicare AEP and must pass underwriting (unless a GI right applies).

D-SNP & C-SNP special enrollment

D-SNP (dual eligible)

Sold during the ICEP, AEP, or MA OEP to those who qualify. Becoming newly dual-eligible opens an SEP. Those eligible for an integrated D-SNP generally get one opportunity per month to elect an integrated plan, as long as they keep both Medicare and Medicaid.

C-SNP (chronic condition)

Normal enrollment is during the IEP/AEP, but a newly documented qualifying chronic condition opens an SEP to join a C-SNP. That SEP is available while the person has the condition and closes once it's used. Moving out of the plan's service area, or the plan leaving Medicare, also opens an SEP.

ACA Marketplace (under-65)

• Open Enrollment Period: Nov 1 – Jan 15 (some state marketplaces run to Jan 31).
• Special Enrollment Period: a qualifying life event (job loss, marriage/divorce, loss of coverage, moving, a new child, etc.) opens an SEP — you must act within 60 days.

See ACA Marketplace (Under-65 Health Insurance).

Compliance: Scope of Appointment (SOA)

Before discussing Medicare Advantage or Part D plans with a beneficiary, an agent must collect a signed Scope of Appointment documenting which product types may be discussed — and CMS requires it generally 48 hours in advance. Certain ancillary products (hospital indemnity; dental/vision/hearing) have an SOA checkbox and can be discussed if marked; others (critical illness, cancer/heart/stroke, short-/long-term care, accident) have no checkbox and are best discussed at separate follow-up appointments outside primary enrollment. See Ancillary (Supplemental) Insurance with Medicare.

See also: Medicare Advantage (Part C), Medicare Supplement (Medigap) Plans & Underwriting, Part D Prescription Drug Coverage, Special Needs Plans — D-SNP, C-SNP & I-SNP, ACA Marketplace (Under-65 Health Insurance), Ancillary (Supplemental) Insurance with Medicare.