Should you decide to purchase travel insurance, you can do so up until 24 hours prior to your departure date. But Elliott warns against buying a plan as an afterthought. He recommends thoroughly researching different providers and types of coverage to determine if a plan is right for you. Websites like SquareMouth.com and InsureMyTrip.com, which allow you to compare policies, are good places to start. Elliott also notes that some insurance companies offer a 30-day post-purchase grace period, allowing you to change your mind for a full refund.
Read the full article from U.S. News and World Report: http://travel.usnews.com/features/Your-Travel-Insurance-Questions-Answered/