Specifically, there is a time sensitive period of 15 days from the date of the initial trip deposit date of the trip. (tripassure.com)
When you make the first trip deposit date is important because it essentially starts the clock on how soon you should purchase your travel insurance if you want certain coverage. (travelinsurancereview.net)
Includes automatic waiver for pre-existing conditions if the plan is purchased within 15 days of your initial trip deposit date. (travelinsurancereview.net)