Add the blueberries and syrup to a small saucepan. Cook on medium heat for 10 minutes.
Use a fork or potato masher to break down the blueberries. Remove from heat and let cool.
Break the 15 graham cracker squares in half so there are 30. Add half to the bottom of a 9 inch baking dish.
Add the Cool Whip to a large bowl then fold in the cooled blueberry mixture. Spread evenly onto the graham crackers.
Top the Cool Whip mixture with another layer of graham crackers. Freeze for 2 hours.