You can change health insurance during your plan’s annual enrollment window, or outside that window if a qualifying life event opens a Special Enrollment Period. For federal Marketplace plans, Open Enrollment runs November 1 through January 15. Job-based plans set their own annual window, usually in the fall. Medicare has its own calendar. Medicaid and CHIP accept applications any time of year.
Marketplace Open Enrollment Dates
The federal Health Insurance Marketplace opens enrollment from November 1 through January 15 each year.1HealthCare.gov. Getting Health Coverage Outside Open Enrollment Within that window you can sign up for a new plan, switch plans, or renew what you already have. Enroll by December 15 and coverage starts January 1. Enroll between December 16 and January 15 and coverage begins February 1.2HealthCare.gov. When Can You Get Health Insurance
Several state-run exchanges extend past January 15. For 2026 coverage, California, Connecticut, the District of Columbia, Illinois, New Jersey, New York, Pennsylvania, and Rhode Island allow enrollment through January 31. Massachusetts extends to January 23 and Virginia to January 30. If you live in one of these states, check the exact date on your state exchange.
Qualifying Events That Let You Change Mid-Year
Outside Open Enrollment, you can only change a Marketplace plan if you experience a qualifying life event. You have 60 days from the event to pick a new plan.1HealthCare.gov. Getting Health Coverage Outside Open Enrollment Miss those 60 days and you wait until the next Open Enrollment.
The most common qualifying events:
- Losing existing coverage: job loss, being dropped from a parent’s plan after turning 26, exhausting COBRA benefits, or losing eligibility for a student health plan.1HealthCare.gov. Getting Health Coverage Outside Open Enrollment
- Changes in household: getting married, having or adopting a baby, placing a child in foster care, or losing a household member through death or divorce.
- Moving to a new ZIP code or county where different plans are available. Moving for vacation or medical treatment does not count.1HealthCare.gov. Getting Health Coverage Outside Open Enrollment
- Being denied Medicaid or CHIP coverage, which can open a Marketplace enrollment window.
Voluntarily dropping your coverage does not qualify. Canceling a plan because you don’t like it is not a loss of coverage in the Marketplace’s eyes.
Proof and When New Coverage Starts
You may need documents confirming the event: a marriage certificate, birth certificate, or court order for household changes, or a letter from your former employer or insurer for job-related coverage loss.3Centers for Medicare & Medicaid Services. Special Enrollment Periods Job Aid On the federal Marketplace, events like marriage and adoption no longer require documents upfront, though you may be asked to verify later.
Effective dates depend on the event. For a birth or adoption, coverage can be retroactive to the date the child arrives. For marriage, coverage typically starts the first of the month after you select a plan. For loss of coverage, coverage usually begins the first of the month after the old plan ends or the first of the month after you make your selection.
Changing a Job-Based Plan
If you get insurance through work, your employer sets an annual enrollment window, usually in the fall for coverage starting the following January. That is your main chance to switch plan options, add or remove family members, or change coverage levels. Outside that window, the same qualifying-life-event rules apply: marriage, birth, loss of a spouse’s coverage, and similar changes let you adjust mid-year through your plan administrator.
One switch worth thinking through carefully: moving from a High Deductible Health Plan to a standard plan mid-year immediately ends your eligibility to make new HSA contributions. Money already in the account stays yours and can still pay qualified medical expenses, but no new deposits are allowed while you are on a non-qualifying plan.4HealthCare.gov. New in 2026 – More Plans Now Work with Health Savings Accounts For 2026, the IRS allows HSA contributions of up to $4,400 for individual coverage and $8,750 for family coverage.5Internal Revenue Service. Expanded Availability of Health Savings Accounts Run the numbers before giving that up.
Medicare Enrollment Windows
Medicare runs on its own calendar with multiple windows, and mistiming enrollment carries permanent financial penalties.
Initial Enrollment Period
When you first become eligible, usually around your 65th birthday, you get a seven-month Initial Enrollment Period. It starts three months before the month you turn 65 and ends three months after.6Medicare. When Does Medicare Coverage Start Signing up earlier in the window means coverage starts sooner.
Medicare Open Enrollment
Medicare Open Enrollment runs October 15 through December 7 each year, with changes taking effect the following January 1.7Medicare. Medicare and You Handbook 2026 In that window you can switch from Original Medicare to a Medicare Advantage plan or back, change Medicare Advantage plans, or join, switch, or drop a Part D prescription drug plan.
General Enrollment and the Medicare Advantage Window
If you missed your Initial Enrollment Period, the General Enrollment Period runs January 1 through March 31 each year, with coverage starting the month after you sign up.8Social Security Administration. When to Sign Up for Medicare Separately, the Medicare Advantage Open Enrollment Period also runs January 1 through March 31 and lets people already in a Medicare Advantage plan make one change: switch to another Advantage plan or drop back to Original Medicare.
The Cost of Enrolling Late
The Part B late enrollment penalty adds 10% to your monthly premium for every full year you could have signed up but didn’t, and it applies for as long as you have Part B.9Medicare. Avoid Late Enrollment Penalties The standard Part B premium for 2026 is $202.90 per month.10Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles Part D carries a separate penalty of 1% of the national base beneficiary premium for each full month you went without creditable drug coverage, recalculated annually and added to your premium.11Centers for Medicare & Medicaid Services. The Part D Late Enrollment Penalty The Part D penalty is avoidable if you had other creditable drug coverage during the gap, such as through an employer plan or the VA.
Medicaid and CHIP Are Year-Round
Medicaid and the Children’s Health Insurance Program don’t follow an annual enrollment schedule. Federal law requires states to accept Medicaid applications at any time and provide coverage promptly to anyone who qualifies.12Office of the Law Revision Counsel. 42 US Code 1396a – State Plans for Medical Assistance CHIP works the same way, with states using tools like presumptive eligibility to cover children quickly.13Medicaid.gov. CHIP Eligibility and Enrollment If your income drops or your household changes so that you qualify, you can apply immediately.
Losing Medicaid or CHIP eligibility also triggers a Special Enrollment Period for Marketplace coverage. If your state determines you no longer qualify, you have 60 days to enroll in a Marketplace plan.
Switching from COBRA to a Marketplace Plan
COBRA lets you keep your former employer’s group health plan temporarily after a job loss or other qualifying event, typically for 18 months and sometimes up to 36 months.14U.S. Department of Labor. COBRA Continuation Coverage You pay the entire premium yourself, plus an administrative fee of up to 2%.15U.S. Department of Labor. FAQs on COBRA Continuation Health Coverage
The common mistake is canceling COBRA early to switch to a Marketplace plan. Voluntarily dropping COBRA outside Open Enrollment is not a qualifying event, and you cannot get a Marketplace plan until the next Open Enrollment. You do get a Special Enrollment Period if your COBRA coverage is actually running out, if your former employer stops contributing and you become responsible for the full cost, or if you are still within 60 days of the original job loss.16HealthCare.gov. COBRA Coverage When You Are Unemployed If you qualify for Medicaid or CHIP, you can enroll at any time regardless of COBRA status.
If You Miss Every Window
If Open Enrollment has passed and you don’t have a qualifying event, your options narrow. Medicaid remains available year-round for those who qualify. Short-term health insurance plans can be purchased at any time in most states and provide temporary coverage, but they are not required to comply with ACA consumer protections. They can exclude preexisting conditions, impose lifetime benefit caps, and skip coverage for services like mental health or prescription drugs. Duration limits vary by state, with some allowing terms of up to three years and others capping them at a few months.
Short-term plans exist to bridge a gap, not to replace comprehensive coverage. If you are between jobs or waiting for employer coverage to start, they can fill the space. Relying on one long-term is a gamble that goes badly the moment you need serious medical care.