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When is the deadline to enroll in 2027 ACA marketplace coverage — December 15 or January 15?

January 15 is the final deadline in HealthCare.gov states — but December 15 is the date that decides whether your coverage starts January 1. The confusion is understandable, because the deadline genuinely almost changed: a 2025 federal rule (the Marketplace Integrity and Affordability rule) would have ended open enrollment on December 15. A federal judge vacated that provision in June 2026, and CMS confirmed the schedule in writing — verified verbatim from the agency's August 2026 statement, "open enrollment at the federally facilitated exchange will begin November 1, 2026, and end January 15, 2027." So the 2027 calendar in the roughly 30 states using HealthCare.gov is: window shopping in late October, enrollment opens November 1, enroll by December 15 for coverage starting January 1, and enrollments from December 16 through January 15 generally start February 1. Treat December 15 as your working deadline anyway — not just for the January 1 start date, but because an appeal of the court ruling is still pending, with oral arguments expected in late October, and because a February 1 start means a full month exposed to medical bills if anything happens in January. One more wrinkle: state-run exchanges set their own calendars. Idaho runs October 15 to December 15; Connecticut and Massachusetts open October 23; California, D.C., New Jersey, and New York extend to January 31; Rhode Island runs to December 31. And stale December-15-deadline articles from the period when the shorter window was on the books are still circulating widely — check your own state's exchange before you trust any date you read, including this one, if you are reading it after the season ends. As Centers for Medicare & Medicaid Services, Agency of the U.S. Department of Health and Human Services, put it on the record before the CMS written statement confirming the PY2027 federal exchange enrollment window, as reported by Medical Daily (Sept. 18, 2026) (2026-08-31): “open enrollment at the federally facilitated exchange will begin November 1, 2026, and end January 15, 2027” For help choosing or enrolling in a plan, call United Enrollment Services, a licensed insurance agency, at 1-866-401-4116.

Last updated Sep 27, 2026
Reviewed by Heather Fabrizio, Licensed Insurance Agent (NPN 20983651) · reviewed Jul 25, 2026
Published by ACA Direct Answers · Licensed under Citation License 1.0

Source citation and speaker credentials

Editor's note: Nov 1 - Jan 15 window, Dec 15 deadline for Jan 1 effective dates, June 2026 vacatur of the shortened-OEP provision, pending appeal with late-October oral arguments, and state-exchange variations (Idaho Oct 15 - Dec 15; CT/MA open Oct 23; CA/DC/NJ/NY to Jan 31; RI to Dec 31) all verified this session from healthinsurance.org''s deadlines FAQ. The CMS August 2026 confirmation quote and Deputy Administrator Peter Nelson''s involvement verified this session from Medical Daily (Sept. 18); the quote is from CMS''s written statement as reported there, and the speaker is recorded as the agency with an approximate August date rather than a named official to avoid over-attribution. The rule name (Marketplace Integrity and Affordability) is from the news proposal''s summary corroborated by Norton Rose/Ritter coverage; the specific court and case name were not verified this session and are deliberately not stated. SSN/immigration-document application requirement verified this session from the CMS Sept. 22 anti-fraud press release.

Who said this

Centers for Medicare & Medicaid Services · Agency of the U.S. Department of Health and Human Services

What it means

  • Two deadlines do two different jobs: December 15 controls whether your coverage begins January 1, while January 15 is the last day to enroll at all in HealthCare.gov states — miss it and you generally wait a year unless a qualifying life event opens a special enrollment period.
  • The shortened Dec. 15 window was real policy that got struck down — a federal judge vacated that provision of the 2025 Marketplace Integrity and Affordability rule in June 2026, which is why so much conflicting information exists online right now.
  • Enrolling between December 16 and January 15 leaves you uninsured for January unless you have other coverage — a hospital visit in that gap month is entirely on you.
  • This is the year not to auto-renew blindly: premiums are rising by double digits in many states, insurers are exiting markets, and new identity-verification requirements (SSN or immigration document number on applications) can slow processing — start early rather than betting on the deadline.
  • If you live in a state-run exchange state, none of the federal dates bind your exchange — several states open earlier or close later than HealthCare.gov.

Action steps

  1. Mark two dates now: November 1 (enrollment opens) and December 15 (deadline for January 1 coverage). Aim to finish before Thanksgiving to leave room for verification hiccups.
  2. Confirm your state's calendar: if you use HealthCare.gov, the Nov 1 - Jan 15 window applies; if your state runs its own exchange (California, New York, Idaho, Massachusetts, and others), check its site directly for open and close dates.
  3. Use window shopping in late October to preview real 2027 plans and prices before enrollment opens — premiums and insurer lineups are changing sharply this year, so your current plan may not be your best option, or may not exist.
  4. Update your application carefully — income, household size, and immigration/SSN details — because applications now require a Social Security number or immigration document number, and mismatches trigger verification delays.
  5. If you miss January 15, check whether you qualify for a special enrollment period (job loss, move, marriage, birth) before assuming you're locked out for the year.

Risks & deadlines

  • December 15, 2026: last day to enroll for January 1 coverage in HealthCare.gov states. January 15, 2027: final deadline; later enrollments generally start February 1.
  • An appeal of the ruling that restored the January 15 end date is pending, with oral arguments expected in late October 2026 — a late-breaking decision is unlikely to change this season's dates, but it is one more reason not to procrastinate past December 15.
  • State exchanges differ: Idaho closes December 15; Rhode Island December 31; California, D.C., New Jersey, and New York run to January 31 — your state's dates, not the federal ones, are the ones that bind you.
  • Outdated articles citing a December 15 final deadline (written when the shorter window was on the books) are still circulating — verify dates against HealthCare.gov or your state exchange before acting on anything you read.

Also asked as

  • Is the Obamacare deadline December 15 or January 15 this year?
  • When does 2027 ACA open enrollment start and end?
  • What happens if I enroll in a marketplace plan after December 15?
  • Did the ACA open enrollment period get shortened for 2027?
  • When do I need to sign up for health insurance for January 1 coverage?

Sources

Last verified: 2026-09-27

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