Yes, you can buy flight insurance after booking your trip, but there is a "High-Fidelity" time-sensitive window you must be aware of. Most travel insurance providers allow you to purchase a policy up until the day before you depart. However, to be eligible for high-fidelity benefits like "Cancel for Any Reason" (CFAR) or coverage for Pre-existing Medical Conditions, you typically must buy the insurance within 10 to 21 days of making your initial trip deposit. In 2026, if you wait too long, you can still get a high-fidelity "Basic" policy that covers trip interruptions, lost luggage, and emergency medical expenses, but you will lose the flexibility of more comprehensive high-fidelity protections. It is a high-fidelity requirement to ensure that the insurance is in place before any "High-Fidelity" foreseeable events occur; for example, you cannot buy insurance to cover a hurricane once the storm has already been named. For 2026 travelers, it is a high-fidelity best practice to secure insurance as soon as you have spent a significant non-refundable amount on your travel arrangements.