The main windows at a glance
| Coverage | Window | Coverage starts |
|---|---|---|
| HealthCare.gov (federal Marketplace) | Nov 1 – Dec 15, 2026 | Jan 1, 2027 if you enroll by Dec 15 |
| State-run Marketplaces | Starts by Nov 1; end dates vary by state (many Dec 31 or mid-January) | Jan 1, 2027 or the first of the next month, depending on the state |
| Medicare Annual Open Enrollment (Advantage and Part D) | Oct 15 – Dec 7, 2026 | Jan 1, 2027 |
| Medicare Advantage Open Enrollment | Jan 1 – Mar 31, 2027 | First of the month after the plan gets your request |
| Employer plans | Set by employer, commonly Oct–Nov | Plan year start, often Jan 1 |
| Medicaid and CHIP | Year-round | Depends on your state |
What to do if you miss the deadline
If open enrollment closes and you have not picked a plan, you generally cannot enroll in a Marketplace or employer plan until the next window, unless you qualify for a special enrollment period (SEP). Qualifying events include losing other coverage (such as a job-based plan), getting married, having a baby or adopting a child, moving to a new area with different plans, and a change in household income that makes you newly eligible for savings in some cases. You usually have 60 days from the event to select a Marketplace plan; employer plans commonly allow 30 days. You will be asked for proof of the event, such as a termination letter. Our life events guide explains what documents help. Medicaid and CHIP are open all year if you qualify.
Auto-renewal can cost you
If you already have a Marketplace plan and do nothing, you are often re-enrolled automatically in the same plan or a similar one. Premiums, deductibles, networks and drug lists change every year, and the subsidy rules for 2027 are different from the last few years. Re-enrolling without checking can mean a much higher bill or a plan that no longer covers your doctor. The same applies to Medicare drug plans. Spend 30 minutes comparing, even if you plan to stay put.
A short timeline for the next six weeks
- Now–Nov 1: collect last year’s claims and your list of medicines and doctors; estimate your 2027 income.
- Nov 1: HealthCare.gov and most state exchanges open; log in or create an account and update your application.
- By Dec 7: Medicare plan changes.
- By Dec 15: select a federal Marketplace plan for coverage that begins January 1; pay the first premium on time, because coverage starts only once the insurer receives payment.
- Dec 31: use up any FSA money subject to a year-end deadline and make final HSA moves if you wish to count them for the year (HSA contributions can be made until the tax deadline).