Yes you can, I would listen to Phamton and wait till you get there and see if you need it since it is completely non-refundable ( all express passes are non-refundable,dated and park specific) .The price for it is usually about $30 more per person then the regular express pass,( remember express pass purchase prices are based on crowds, the higher the crowds the more the passes) so if the regular pass is $34.95 for the day ( one of the cheaper days), the unlimited would be about $65 a person ( not including park tickets). though you can buy ticket/pass combos..Do the math though,if you are there during crowded times and have 3-4 people in your group, it may be cheaper to book a deluxe resort for the night and get the pass access that way