Pit and halve the dates and soak them in room temperature water for 10-15 minutes. Add all ingredients to the blender (except the chia seeds), and blend on high speed until the mixture is smooth.
Pour blueberry mixture into a bowl and whisk in chia seeds. Let sit for 5 minutes and whisk again.
Cover and store in the refrigerator for 2-3 hours at a minimum, or overnight. If you can, give the pudding a good stir two to three times while it is in the refrigerator to prevent the chia seeds from clumping together.