Pour sand into the tub, tray or box. You can use any type of container you have on hand; a container with a lid will allow you to easily put it away for another time. If you don't have sand, use corn meal, flour or anything else you have on hand that resembles sand.
Add blue pebbles, marbles or rice on one side. This should resemble the water coming up over the sand.
Place spoons in the container for each digging and moving of the sand. Add in the small toys, sea shells and little containers. Children love to scoop and pour the sand in and out of the containers. Bury the sea shells and small toys, like small palm trees, crabs or sea animals, or place them on top of the sand.