ACA Open Enrollment for 2027 Runs Nov. 1 to Jan. 15 After a Court Blocked a Shorter Window

Open enrollment for 2027 Affordable Care Act (ACA) health plans on HealthCare.gov opened Sunday, Nov. 1, 2026, and closes Friday, Jan. 15, 2027, according to the federal Marketplace. The date that matters most is Tuesday, Dec. 15: pick a plan and pay the first premium by then, and coverage starts Jan. 1. The window stays the length it has been in recent years because a federal court blocked a 2025 rule that would have ended it on Dec. 15.

ACA open enrollment 2027 dates

Date	What happens
Sunday, Nov. 1, 2026	Open enrollment began on HealthCare.gov
Tuesday, Dec. 15, 2026	Last day to enroll or change plans for coverage starting Jan. 1
Friday, Jan. 1, 2027	Coverage begins for plans chosen and paid for by Dec. 15
Friday, Jan. 15, 2027	Open enrollment ends; plans chosen Dec. 16 to Jan. 15 begin Feb. 1

The Centers for Medicare & Medicaid Services (CMS) confirms the Nov. 1 to Jan. 15 window for 2027 HealthCare.gov coverage in its Plan Year 2027 fact sheet of Oct. 30, 2026. HealthCare.gov’s dates page lists Dec. 15 as the “last day to enroll in or change plans for coverage to start January 1.”

CMS figure for 2027	What it says
Premiums at or below $50	More than 75% of Americans who buy through HealthCare.gov will continue to have access to them
Plans and insurers	On average, Americans have access to 100 different plans and five to six different insurance companies

After Jan. 15 you can enroll only with a Special Enrollment Period, which requires a qualifying life event such as losing other coverage, moving, marriage or the birth of a child.

Why the window was not shortened

In June 2025 CMS finalized the Marketplace Integrity and Affordability rule. Among other changes, it required every marketplace to end open enrollment by Dec. 31 and cap it at nine weeks starting with 2027 plans, which would have meant a Dec. 15 close on HealthCare.gov.

Cities and advocacy groups sued. In June 2026 the U.S. District Court for the District of Maryland vacated that open-enrollment provision, along with several others, in City of Columbus v. Kennedy, according to the Georgetown Law Health Care Litigation Tracker. HealthCare.gov now lists the familiar Nov. 1 to Jan. 15 window. The administration has appealed to the Fourth Circuit (No. 26-1938), which set oral argument for Oct. 30, 2026, according to the tracker. That date has passed, and this story has no report on the argument. No stay of the lower court’s order had been issued as of Oct. 26, and HealthCare.gov still lists Jan. 15 as the last day.

States with their own marketplaces

About 20 states and Washington, D.C., run their own exchanges instead of using HealthCare.gov, and they set their own calendars. Some open earlier or stay open later; California’s Covered California, for example, has traditionally run past Jan. 15. If your state has its own site, check its dates rather than HealthCare.gov’s. HealthCare.gov will send you to your state’s marketplace when you enter your ZIP code.

Before you log in

1. Update your income. Subsidies, called premium tax credits, are based on your expected 2027 household income. An outdated figure can mean a surprise bill at tax time.
2. Compare total cost, not just the premium. A cheaper monthly premium can come with a much higher deductible.
3. Check doctors and prescriptions. Networks and drug lists change every year.
4. Don’t rely on automatic re-enrollment. HealthCare.gov may renew you into the same or a similar plan, but the price can change.

Our free checklist lists the documents to have ready, from Social Security numbers to income records and current policy numbers.

Not the same as Medicare open enrollment

People with Medicare have a separate window, Oct. 15 to Dec. 7, 2026, covered in our Medicare open enrollment guide. Retirees watching costs can also see how the 3.6% Social Security raise for 2027 lands in January.

Mark the dates

Open enrollment began Nov. 1 (see the November 2026 calendar); circle Dec. 15 on the December 2026 calendar and Jan. 15 on the January 2027 calendar. Free help is available through HealthCare.gov’s Find Local Help tool or the Marketplace call center at 1-800-318-2596.

People with Medicare have a separate window; see Medicare open enrollment, ending Dec. 7.