Bogg Bags are designed to be sand-resistant, but they are not completely sand-proof. If you are playing in the sand, there is a chance that some sand will get into the bag. However, the holes in the material of the bag will allow most of the sand to fall out. The best part is that if you do get sand in your Bogg Bag, you can easily rinse it out with water. The holes in the material will allow the water to drain out, and the sand will be washed away.