The US has no single public health system for everyone. Most people get insurance from one of these places.
Many employers offer a plan for you, your spouse and your children. The employer usually pays a large part of the premium.
You usually have about 30 days from your start date to sign up. Ask HR on your first day.
Look at the plan options, the deductible and whether your family can join.
If you miss the window, you usually wait until the yearly enrollment period at work.
F-1 and M-1 students: there is no federal insurance rule, but most universities require a plan. Many enroll you automatically and add the cost to your tuition bill.
Waiver: some schools let you skip the school plan if you already have a plan that meets their rules. You must apply before the school's deadline, usually in the first weeks of the term. Read the rules carefully. A cheap plan that the school rejects means you pay for both.
J-1 exchange visitors and J-2 family members: federal rules require insurance for the whole program with at least $100,000 of medical benefits per accident or illness, $25,000 for sending remains home, $50,000 for medical evacuation, and a deductible of no more than $500. Your sponsor checks this. Not keeping it can end your program.
The Marketplace (healthcare.gov, or your state's own site) sells private plans to people who buy their own insurance. Some people get a premium tax credit, a discount on the monthly premium, based on income and immigration status. See the guide "Health insurance by visa status: F-1, H-1B, green card".
Medicaid is public insurance for people with low income. CHIP covers children (and in some states pregnant people) in families who earn too much for Medicaid. They are run by states, so the rules differ by state. Many immigrants must wait five years. Read the status guide and the public charge guide before you apply.
5. Visitor or travel insurance
Tourists and visiting parents cannot usually buy Marketplace plans. They buy short-term visitor insurance before or soon after arrival. See the guide "Health insurance for visiting parents and B-2 visitors".
Refugees can get Refugee Medical Assistance for a limited number of months after arrival, and a health screening. Your resettlement agency helps you apply. Rules changed in 2025 and 2026, so ask the agency what applies to you.
Waiting to "see if you need it". One emergency room visit can cost thousands of dollars.
Missing the 30-day window at a new job or the school waiver deadline.
Buying a plan that is not real insurance. Some "health sharing" or discount plans do not have to pay your bills. Ask: "Is this an ACA-compliant plan?"