The short answer: on HealthCare.gov, Open Enrollment for 2027 starts November 1. Enroll or change plans by December 15 and pay your first premium, and coverage starts January 1. Enroll December 16 through January 15 and pay your first premium, and coverage starts February 1. After January 15 you need a Special Enrollment Period. A few state-run exchanges use their own windows, and private plans do not use this window at all.
The four dates, in plain language
- November 1. The first day you can enroll in, renew or change a Marketplace plan for 2027.
- December 15. The last day to enroll or change plans for coverage that starts January 1.
- January 1. Coverage starts for people who enrolled or changed plans by December 15 and paid their first premium.
- January 15. Open Enrollment ends. Enroll December 16 through January 15 and pay your first premium, and coverage starts February 1.
The first premium is part of the deadline. Picking a plan is not the same as being covered: the dates above start coverage only once that first payment is made.
Picture it
Your current plan ends December 31. December is busy, so you tell yourself you have until the middle of January and you enroll on January 10. Then you read the confirmation: your new plan starts February 1. January sits in between, with no plan at all, right when a child brings home the flu.
Now picture the other version. You mark December 15 on the calendar, not January 15. You compare plans in the first week of December, enroll, pay the first premium, and your new plan is waiting for you on January 1.
Your state may use its own dates
The dates above are HealthCare.gov's, and in most states those are the dates that apply. A few state-run exchanges use their own windows, so check your state's own exchange before you count on December 15 or January 15. One example for 2027: HealthCare.gov says Oregon residents use ExploreHealthOR.gov to enroll in 2027 coverage starting November 1. Tell us your state and we confirm the dates that apply to you.
Already on a Marketplace plan?
If you have Marketplace coverage in December and take no action by December 15, HealthCare.gov says it will automatically re-enroll you, either in your current plan or in a different plan from the same insurance company. Plans and prices change each year, so HealthCare.gov's own advice is to update your expected income and household information and compare plans before you renew. What doing nothing can cost you.
Private plans do not follow these dates
Open Enrollment is the Marketplace's window. Private health plans enroll year-round, and for most private plans on our site, applications submitted by the 23rd of the month start on the 1st of the next month. They ask health questions and approval is the carrier's decision, so they suit some people better than others. If your income qualifies for income-based savings, or a health condition means a private plan will not accept you, the Marketplace is usually the right call. If not, a private plan's full price is often lower than an unsubsidized ACA plan for a healthy applicant. Do you have to use the Marketplace?
Missed January 15?
After January 15 you can enroll in or change a Marketplace plan only if you qualify for a Special Enrollment Period, such as after losing health coverage, moving, getting married, having a baby or adopting a child. You generally have about 60 days from the event to enroll, so note the date it happened. A private plan is still open any month. See which doors are still open, or read when new coverage starts on each path.
This is general education, not tax advice and not a guarantee of coverage. Dates shown are HealthCare.gov's for 2027 coverage; state-run exchanges can set their own. Approval, start dates and eligibility depend on the carrier, your state and underwriting.