Research note · Calendars

Open enrollment & Medicare AEP calendar 2026 to 2027 (plain English)

Open enrollment windows are short. Missing them usually means waiting, unless a Special Enrollment Period applies.

This page collects Marketplace Open Enrollment and Medicare Annual Enrollment Period (AEP) dates in one place, with links to the official sources. Always confirm on HealthCare.gov or Medicare.gov before you act.

Last reviewed: 2026-09-13 (dates pulled from HealthCare.gov / Medicare.gov / CMS materials for the 2026-2027 cycle).

Marketplace Open Enrollment

Window	Who	When (2026-2027 cycle)	What it is for	Official source
Marketplace Open Enrollment	Most people shopping for ACA Marketplace coverage	November 1, 2026 - January 15, 2027	Enroll in, renew, or change Marketplace plans for 2027 coverage	HealthCare.gov dates & deadlines
January 1 start deadline	Marketplace shoppers who want coverage to start January 1	Enroll by December 15, 2026	Last day for January 1 effective date (if you pay the first premium)	Same HealthCare.gov page
February 1 start	Marketplace shoppers who enroll later in OE	Enroll December 16, 2026 - January 15, 2027	Coverage can start February 1 (if you pay the first premium)	Same HealthCare.gov page

Note: If your state runs its own Marketplace (not HealthCare.gov), end dates can differ, always check your state site and confirm on HealthCare.gov dates & deadlines.

What changed for 2027 (the higher out-of-pocket limit and how tax credits are described now) is in when is Open Enrollment for 2027.

Outside Open Enrollment, Marketplace enrollment or plan changes usually require a Special Enrollment Period based on a qualifying life event (or other SEP rules). Medicaid and CHIP applications can happen year-round. See coverage outside Open Enrollment.

Job-based plans often use different employer OE windows, check with your employer.

Dual-track timeline showing Marketplace Open Enrollment from November 1, 2026 to January 15, 2027 and Medicare Annual Enrollment from October 15 to December 7, 2026, with October 1 compare-ahead and January to March MA-OEP/GEP notes; verify on official .gov sites. — Figure 1. Annual dual-track timeline for Marketplace Open Enrollment and Medicare AEP (2026-2027 cycle). Verify on .gov.

Medicare Annual Enrollment Period (AEP)

Window	Who	When (2026-2027 cycle)	What it is for	Official source
Medicare Open Enrollment / AEP	People with Medicare	October 15 - December 7, 2026	Join, switch, or drop Medicare Advantage and/or Part D drug coverage; switch between Medicare Advantage and Original Medicare for 2027 (plan must receive your request by December 7)	Medicare.gov Open Enrollment
Compare ahead	People with Medicare	From October 1, 2026	Start comparing 2027 plan options before AEP opens	Medicare.gov Open Enrollment / Medicare & You 2026

Changes made during AEP generally take effect January 1, 2027 when the plan receives a timely enrollment request.

Row of deadline chips for Marketplace Open Enrollment and Medicare AEP including November 1, December 15, December 16 to January 15, January 15, October 1 compare-ahead, October 15 to December 7 AEP, and January to March MA-OEP/GEP; verify on .gov. — Figure 2. Callout chips for Marketplace and Medicare deadlines in the 2026-2027 cycle. Always re-check .gov.

Window	Who	When	What it is for	Official source
Medicare Advantage Open Enrollment Period (MA-OEP)	People already in a Medicare Advantage Plan	January 1 - March 31 each year	Switch to another Medicare Advantage Plan, or switch to Original Medicare (and usually join a separate drug plan). You generally cannot use MA-OEP to move from Original Medicare into Medicare Advantage.	Medicare.gov / Medicare & You handbook
General Enrollment Period (Part A/B)	People who missed Initial Enrollment and do not have another SEP	January 1 - March 31 each year	Sign up for Part B (and Part A if you do not qualify for premium-free Part A). Coverage timing and possible late-enrollment penalties are on Medicare.gov.	Medicare.gov

Medigap (Medicare Supplement) timing has separate guaranteed-issue and underwriting rules. This page does not replace Medigap advice, start at Medicare.gov Medigap materials if that is your question.

Special Enrollment Periods (overview)

SEPs exist for certain life events and situations (for example losing other coverage, moving, marriage, birth/adoption, and other qualifying events). Rules differ for Marketplace vs Medicare.

Marketplace SEP overview: HealthCare.gov, coverage outside Open Enrollment
Medicare plan-change timing: Medicare.gov Open Enrollment

This is not an exhaustive legal list. If you think you qualify, confirm on the .gov site that applies to you.

Simple decision tree for enrollment outside main windows, branching to Marketplace Special Enrollment Period guidance on HealthCare.gov versus Medicare timing guidance on Medicare.gov; states it is not an exhaustive list. — Figure 3. High-level SEP overview that routes Marketplace vs Medicare readers to official .gov pages.

How to use this calendar in a Free Healthcare Review

Bring this page and your current cards or EOBs to a free healthcare review. Useful prep:

Circle the next window that applies to you (Marketplace OE, Medicare AEP, MA-OEP, or a possible SEP).
Write one sentence: what you want to change (or keep) before that deadline.
Walk the healthcare review checklist so documents and questions are ready.

AFHC can help you organize a household plan conversation. Official enrollment still happens on HealthCare.gov, Medicare.gov, or your plan, we do not invent dates or promise outcomes.

Walk the healthcare review checklist so documents and questions are ready before the deadline.

For Medicare product basics beyond AEP timing, see Medicare.

OE season raises ad noise. Read medical insurance scams before you pay a cold-call pitch.

Browse the research library.
Prep documents with the healthcare review checklist.
Read what underinsured means if you already have a card.
Review Medicare basics on Medicare.
Watch for OE-season pitches on medical insurance scams.

FAQ

When is Marketplace Open Enrollment for 2027 coverage?

HealthCare.gov states Open Enrollment for 2027 coverage starts November 1, 2026 and runs through January 15, 2027. Enroll by December 15, 2026 for a January 1 start, or by January 15 for a February 1 start (if you pay the first premium). Always re-check HealthCare.gov.

When is Medicare Annual Enrollment Period (AEP)?

Medicare Open Enrollment / AEP runs October 15 through December 7. For the 2026-2027 cycle, that is October 15-December 7, 2026, with changes generally effective January 1, 2027 when the plan receives a timely request. Confirm on Medicare.gov.

What is the Medicare Advantage Open Enrollment Period (MA-OEP)?

If you are already in a Medicare Advantage Plan, MA-OEP (January 1-March 31) lets you switch to another Medicare Advantage Plan or switch to Original Medicare (often with a separate drug plan). It is not the same as AEP. See Medicare.gov.

Can I enroll outside these windows?

Sometimes, through a Special Enrollment Period if you qualify. Marketplace and Medicare SEP rules differ. Start with HealthCare.gov or Medicare.gov, do not rely on an unofficial date list.

Does AFHC enroll me on HealthCare.gov or Medicare.gov for me?

Official enrollment actions happen through government or plan channels. A free healthcare review can help you prepare documents, questions, and timing. It is educational help, not a guarantee you will beat a deadline or lower a premium.

Method / disclaimer

Dates above were assembled from HealthCare.gov and Medicare.gov / CMS consumer materials on 2026-09-13. Government sites update. Verify before you act. This page is educational only, not medical, legal, or personalized insurance advice.

Next step

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Medicare timing and product basics: Medicare.