Put 1 tablespoon of yogurt into each popsicle mold. Put 2 raspberries, halved, into each mold. Put another tablespoon of yogurt into each mold. Add 3-4 blueberries on top, depending on the size of the blueberry. Repeat this process until the molds are almost full, making sure to end with a layer of yogurt.
Insert the popsicle sticks. Freeze for at least 6 hours (preferably overnight). When ready to serve, put molds under running warm water from the tap for 10-15 secs, then carefully remove the popsicles.