Marketplace open enrollment runs once a year. For 2027 coverage it runs November 1, 2026 through January 15, 2027 in most states, with December 15 as the deadline to have coverage start January 1. If you miss that window, you are generally locked out until the next one, unless something in your life changes. Those changes open special enrollment periods, and knowing what counts can be the difference between having coverage and going without it for months.
A special enrollment period, or SEP, is a limited window, usually 60 days, during which a qualifying life event lets you enroll in a Marketplace plan or change your existing plan outside open enrollment. The clock normally starts on the date of the event, so acting quickly matters. For loss of coverage, you get a head start: you can enroll in the 60 days before your old coverage ends as well as the 60 days after, which lets you avoid any gap at all if you plan ahead.
Your coverage start date depends on the event and on when you enroll within the window. Some events trigger coverage on the first of the following month; birth or adoption can trigger coverage backdated to the date of the event. The Marketplace shows your exact start date when you complete enrollment.
The Marketplace recognizes four broad categories of qualifying events.
Loss of qualifying coverage. This is the most common trigger. It includes losing job-based coverage, aging off a parent's plan at 26, COBRA coverage ending, losing eligibility for Medicaid or CHIP, and losing coverage through a divorce or the death of the policyholder. Voluntarily dropping a plan you could have kept does not count, and neither does losing coverage because you failed to pay premiums.
Household changes. Getting married opens a window for both spouses. Having a baby, adopting a child, or taking in a foster child opens one for the whole household. Divorce or legal separation that causes a loss of coverage qualifies, as does the death of an enrolled household member that leaves survivors needing their own plan.
Residence changes. Moving to a new zip code, county, or state where different plans are available generally qualifies, as does a student moving to or from school, a seasonal worker moving for a job, or a move to or from a shelter or transitional housing. A short trip or a temporary address change does not count; the move has to change the plans available to you.
Other qualifying changes. A change in income that affects your eligibility for the premium tax credit or cost-sharing reductions can qualify. Gaining citizenship or lawful presence, release from incarceration, completing AmeriCorps service, and certain errors or misrepresentations in your original enrollment can also open a window. Members of federally recognized tribes and Alaska Native shareholders can enroll or change plans once per month year-round, a standing exception to the usual rules.
The Marketplace may ask you to document your event before your enrollment is finalized. Typical proof includes a letter showing your old coverage end date, a marriage certificate, a birth certificate or adoption paperwork, or a lease, utility bill, or similar document showing a move. Upload what is asked for promptly. If verification is still pending when your window closes, your enrollment can stall, so treat document requests as urgent.
When you apply through a special enrollment period, you still complete the same income application as during open enrollment, which means your premium tax credit is computed the same way. A mid-year income change is also worth reporting even if it does not open a new enrollment window, because it changes your advance credit going forward and reduces the reconciliation surprise at tax time.
One important exception: Medicaid and the Children's Health Insurance Program accept applications year-round. If your income or household situation makes you eligible, you do not need open enrollment or a qualifying event. The Marketplace application screens for Medicaid and CHIP automatically, so a single application routes you to the right program.
Special enrollment rules can vary slightly by state, and state-based Marketplaces sometimes add their own qualifying events. When in doubt, start an application on HealthCare.gov or your state Marketplace and let the eligibility system tell you whether you qualify. The application itself costs nothing, and the worst outcome is learning you need to wait for open enrollment.
A special enrollment period is a window outside open enrollment when a qualifying life event lets you enroll in or change Marketplace coverage. It usually lasts 60 days from the event.
Common qualifying events include losing other health coverage, getting married, having or adopting a child, moving to a new area, and certain income changes that affect your eligibility for financial help.
Most special enrollment periods last 60 days from the date of the event. For loss of coverage, you can also enroll in the 60 days before your coverage ends.
Yes. Medicaid and CHIP enrollment is open year-round for people who qualify, so no special enrollment period is needed.