ACA open enrollment dates for 2027 coverage on HealthCare.gov are November 1, 2026, through January 15, 2027, as checked on HealthCare.gov on October 18, 2026. Pick a plan by December 15 and your coverage can start January 1. Pick a plan between December 16 and January 15 and it starts February 1.

That schedule is the same one used for 2026 coverage. It looked like it would change: a federal rule adopted in 2025 would have cut the 2027 window to end on December 15. A federal court threw out that part of the rule in June 2026, so the familiar dates stayed. This guide explains the dates for both plan years, how state-run exchanges differ, when coverage starts, and what to do if you miss the window.

What are the ACA open enrollment dates for 2026 and 2027?

On HealthCare.gov, both plan years use a November 1 to January 15 window. The table shows the key dates, based on HealthCare.gov and CMS as checked October 18, 2026.

Plan yearOpen enrollment startsLast day for January 1 startOpen enrollment endsCoverage starts if you enroll late in the window
2026November 1, 2025December 15, 2025January 15, 2026February 1, 2026 (for sign-ups December 16 to January 15)
2027November 1, 2026December 15, 2026January 15, 2027February 1, 2027 (for sign-ups December 16 to January 15)

The 2026 window is finished. If you need coverage for the rest of 2026, you need a Special Enrollment Period (see below) or Medicaid or CHIP, which accept applications all year.

When does Marketplace coverage start?

Coverage starts on the first day of a month, and only after you pay your first premium. On HealthCare.gov, the date depends on when you pick your plan:

  1. Plan picked November 1 to December 15: coverage starts January 1.
  2. Plan picked December 16 to January 15: coverage starts February 1.
  3. After January 15: you can only enroll with a Special Enrollment Period, and the start date depends on the type of event.

Picking a plan is not the last step. The insurance company sends a bill for your first month, called a binder payment. Your plan is not active until that payment is made by the insurer’s due date. If you already have a Marketplace plan and do nothing, you may be re-enrolled automatically, but your premium and tax credit can change from one year to the next.

Why did the 2027 open enrollment period almost get shorter?

In June 2025, the Centers for Medicare & Medicaid Services (CMS) adopted the Marketplace Integrity and Affordability rule. CMS training slides on the rule said that, starting with 2027 coverage, open enrollment on HealthCare.gov would run November 1 to December 15, 2026, about 6.5 weeks instead of 10.5. The same rule said every exchange, including state-run ones, would have to start by November 1, end by December 31 and last no more than nine weeks.

Cities and other groups sued. Here is what happened, based on CMS and a litigation tracker from State Health and Value Strategies:

  • August 22, 2025: a federal court in Maryland, in City of Columbus v. Kennedy, paused (stayed) several other parts of the rule before they took effect. The open enrollment change was not one of them, because it was not due to start until the 2027 plan year.
  • June 12, 2026: the same court vacated nine provisions of the rule, including the shorter open enrollment period. “Vacated” means the court set the provision aside, so it does not apply.
  • July 16, 2026: the government filed notice that it will appeal to the Fourth Circuit Court of Appeals. A separate lawsuit by a group of states, California v. Kennedy, was still pending in Massachusetts as of July 2026.

As of October 18, 2026, HealthCare.gov lists November 1 to January 15 for 2027 coverage. The text of the vacated rule still appears in the online Code of Federal Regulations, which is normal after a court ruling, so do not rely on the regulation text alone.

How do state exchange open enrollment dates work?

If your state runs its own exchange, that exchange sets the dates, and they are often longer than HealthCare.gov’s. Before the 2025 rule, federal regulations already allowed state exchanges to keep open enrollment going after January 15, and many did.

For example, Covered California’s site says its open enrollment runs November 1 to January 31, and that you must enroll by December 31 for a plan that starts January 1 (checked October 18, 2026). Other states publish their own deadlines, which can differ from both California’s and HealthCare.gov’s.

Where you liveWho sets the datesWhere to check
A state that uses HealthCare.govCMSHealthCare.gov dates and deadlines page
A state with its own exchange (for example California, New York, New Jersey, Pennsylvania)The state exchangeYour state exchange’s website
Oregon, for 2027 coverageOregon’s new state exchangeHealthCare.gov says Oregon residents use ExploreHealthOR.gov starting November 1, 2026

What can you do during open enrollment?

Open enrollment is the one time each year when you can make almost any change without a life event. During the window you can:

  • Sign up for the first time, even if you had no coverage last year.
  • Switch plans or metal levels, for example from bronze to silver. Our guide to ACA metal levels explains the trade-offs.
  • Update your income and household so your premium tax credit matches what you expect to earn.
  • Add or drop people, such as a child who no longer needs a parent’s plan.
  • Check whether you now qualify for extra savings on deductibles and copays, known as cost-sharing reductions, which only come with silver plans.

How should you prepare before November 1?

A little preparation makes the window easy. Use this checklist in October.

  1. Find your current plan details. Note your premium, deductible and out-of-pocket maximum, and whether your doctors and drugs are covered.
  2. Estimate next year’s income. Marketplace savings are based on the income you expect for the coverage year, not last year. Start with your adjusted gross income and adjust for raises, job changes or self-employment swings.
  3. List everyone in your tax household. That is usually you, your spouse and anyone you claim as a dependent, even if they do not need coverage.
  4. Gather documents. Social Security numbers, immigration documents if they apply, pay stubs, and any job-based coverage offer for anyone in the household.
  5. Read your renewal notice. Insurers and the Marketplace send notices in the fall. They show what your plan will cost next year if you do nothing.
  6. Compare total costs, not just premiums. A cheap premium can mean a high deductible. The approach in our guide on how to compare insurance quotes works here too: compare like with like.

What if you miss open enrollment?

If you miss the window, you can usually only get a Marketplace plan through a Special Enrollment Period. Common qualifying events include losing other coverage, moving to a new ZIP code or county, getting married, or having or adopting a child. In most cases you have 60 days from the event to pick a plan. Our guide to Special Enrollment Periods covers the rules and documents.

Two other doors stay open all year:

  • Medicaid and CHIP: you can apply any time, and if you qualify, coverage can start right away.
  • Job-based coverage: employers run their own open enrollment periods, and job-based plans must offer a special enrollment window of at least 30 days after certain events.

Do the open enrollment dates affect your taxes?

Indirectly, yes. If you enroll and use advance payments of the premium tax credit, you must file a federal tax return and reconcile those payments on IRS Form 8962. For coverage in 2026 and later, the IRS says you must repay the full amount of any excess advance credit, because the old repayment caps were removed for tax years after 2025. Updating your income during open enrollment is the easiest way to avoid a surprise. The premium tax credit guide explains how reconciliation works.

Can you change plans after open enrollment ends?

Usually not, unless something in your life changes. Once January 15 passes on HealthCare.gov, the plan you picked is generally the plan you keep for the rest of the year. A Special Enrollment Period lets you change plans, but HealthCare.gov says that for the most common events, such as moving or losing other coverage, people who already have a Marketplace plan can usually only pick a new plan in the same metal level.

There are a few exceptions. If your income changes and you newly qualify for cost-sharing reductions, you can move to a silver plan to use them. If you lose those savings, you can choose a bronze, silver or gold plan. You should still report income and household changes to the Marketplace during the year, even when you cannot switch plans, because they change the tax credit you are owed. Reporting promptly keeps your monthly payment closer to the right amount and makes tax time simpler.

Quick answers on dates

  • Earliest you can enroll for 2027: November 1, 2026.
  • Deadline for January 1, 2027 coverage on HealthCare.gov: December 15, 2026.
  • Last day of open enrollment on HealthCare.gov: January 15, 2027.
  • Coverage start for January sign-ups: February 1, 2027.
  • State exchanges: set their own dates; Covered California, for example, ends January 31, 2027.

All dates were checked on HealthCare.gov, CMS and Covered California on October 18, 2026. Because an appeal is pending, confirm on HealthCare.gov or your state exchange before you rely on any deadline. We are an independent publication, not an enrollment site or a government agency; final eligibility and prices are set when you apply.