Millions of Americans who buy health insurance through the Affordable Care Act (ACA) Marketplace will have an important opportunity to review their coverage beginning November 1, 2026.
For the 2027 plan year, however, consumers should pay close attention to the enrollment calendar because the federal Marketplace is changing its Open Enrollment schedule. For plans offered through the federal platform, the 2027 Open Enrollment Period will run from November 1 through December 15, 2026. State-based Marketplaces have some flexibility and must end their enrollment periods no later than December 31. CMS
That makes preparation especially important for anyone who wants coverage beginning January 1, 2027.
When Does 2027 ACA Open Enrollment Begin?
The 2027 ACA Open Enrollment Period begins November 1, 2026.
Starting that day, consumers can review Marketplace plans, update their applications, compare available coverage and enroll in a plan for the new year.
For consumers using the federal Marketplace platform, the enrollment period ends December 15, 2026. CMS confirmed this change as part of its rules for the 2027 plan year. CMS
This is an important change from previous years, when the federal Open Enrollment Period generally extended through January 15.
The Most Important 2027 Deadlines
For people planning to purchase ACA Marketplace coverage for 2027, these are the dates to keep in mind:
November 1, 2026: Open Enrollment begins.
December 15, 2026: Deadline on the federal Marketplace for selecting or changing a plan for coverage beginning January 1, 2027.
January 1, 2027: Coverage begins for consumers who completed enrollment by the December 15 deadline and paid any required first premium.
State-based Marketplaces can establish their own dates within the federal requirements. For 2027, they must begin no later than November 1 and end no later than December 31, and the enrollment period cannot exceed nine calendar weeks. CMS
Because deadlines can vary by state, consumers should check the Marketplace serving their state rather than assuming that every state follows exactly the same final date.
Why December 15 Matters
The December 15 deadline is particularly important for consumers who want their new coverage to begin on January 1.
HealthCare.gov currently advises consumers to update their application and enroll by December 15 for January 1 coverage. HealthCare.gov
Waiting until the final day can also create practical problems. Consumers may discover that they need additional documentation, have incorrect income information or need more time to compare plans.
Starting the process early gives applicants an opportunity to address those issues before the deadline.
Don’t Automatically Renew Your Current Plan
If you already have ACA Marketplace coverage, you may be automatically re-enrolled in coverage for the following year. But automatic renewal does not necessarily mean your existing plan will have exactly the same premium, benefits, provider network or cost-sharing structure.
HealthCare.gov advises current enrollees to update their expected income and household information and compare the plans available for the upcoming year. HealthCare.gov
Your current insurance company should also provide information about your coverage for the coming year. Consumers should carefully review those notices rather than assuming that nothing has changed.
Check Your Income and Household Information
Your income and household information can affect eligibility for Marketplace savings.
When applying for 2027 coverage, consumers should provide an updated estimate of their expected household income for the year they are seeking coverage. HealthCare.gov notes that Marketplace savings are based on expected income for the coverage year rather than simply relying on previous-year income. HealthCare.gov
Changes such as a new job, reduced working hours, marriage, divorce or changes in household size can affect eligibility and the amount of financial assistance available.
Updating this information can help ensure that the Marketplace calculates eligibility using the most accurate information available.
Compare More Than the Monthly Premium
The cheapest monthly premium is not necessarily the lowest-cost option overall.
When comparing 2027 plans, consumers should examine:
- Monthly premium
- Deductible
- Copayments
- Coinsurance
- Maximum out-of-pocket costs
- Prescription drug coverage
- Doctor and hospital networks
- Specialist costs
- Coverage for ongoing treatments
A plan with a lower monthly premium could have a higher deductible or greater out-of-pocket costs when medical services are used.
Consumers who regularly visit doctors, take prescription medications or anticipate medical treatment should pay particular attention to these details.
What Happens If You Miss the Deadline?
For consumers on the federal Marketplace, missing the December 15 deadline can affect the start date of coverage.
HealthCare.gov says consumers can still enroll during the period through January 15 under its current general enrollment guidance, with coverage beginning February 1 for qualifying enrollments after December 15. However, CMS’s final rule for plan year 2027 changes the federal Marketplace Open Enrollment Period to November 1 through December 15. HealthCare.gov
This distinction is important because official consumer pages currently contain general Open Enrollment information that still references January 15, while CMS’s final rule specifically establishes the shorter federal-platform schedule for 2027.
For 2027, consumers should therefore follow the specific dates provided by the Marketplace serving their state.
Special Enrollment Periods May Still Be Available
Missing Open Enrollment does not necessarily mean someone has no opportunity to obtain Marketplace coverage.
People who experience certain qualifying life events may be eligible for a Special Enrollment Period (SEP). Examples can include losing qualifying health coverage, getting married, having a baby, adopting a child or moving under qualifying circumstances. HealthCare.gov
In many cases, consumers have a limited period following a qualifying event to select a new plan, so it is important to report the event promptly.
Medicaid and the Children’s Health Insurance Program (CHIP) also operate outside the annual Marketplace Open Enrollment schedule for people who qualify. HealthCare.gov
How to Prepare Before November 1
Consumers can make the enrollment process easier by gathering important information ahead of time.
Before Open Enrollment begins, consider collecting:
- Estimated 2027 household income
- Information about household members
- Current insurance details
- Prescription medication lists
- Preferred doctors and hospitals
- Expected healthcare needs
- Questions about deductibles and out-of-pocket costs
It is also useful to create or verify your Marketplace account before enrollment begins.
HealthCare.gov provides several ways to apply, including online applications, telephone assistance, certified enrollment partners and local enrollment assistance. HealthCare.gov
The Bottom Line for 2027
The 2027 ACA Open Enrollment Period brings an important scheduling change for consumers using the federal Marketplace.
November 1, 2026 marks the start of enrollment, while December 15, 2026 is the key federal-platform deadline for selecting coverage that begins January 1, 2027. State-based Marketplaces may have different final dates within the federal limits. CMS
Rather than waiting until the deadline, consumers should review their income, household information and healthcare needs early, compare available plans and carefully examine premiums and out-of-pocket costs.
For anyone relying on ACA coverage, the 2027 enrollment period is a chance not only to renew insurance, but also to reassess whether the coverage selected for the new year still fits their circumstances.