Working as a team can be a blast when you're on a hunt! Here's a simple game that will keep your kids entertained at the beach.
Give your kids a list of items they must work together to find: 3 types of seaweed, 4 kinds of shells, a perfectly round pebble, a piece of beach glass, a crab claw, a stone with a stripe across it, a seagull feather, a bivalve shell with both halves still joined together, a piece of driftwood with a hole in it, and the like.
Also challenge them to find a mystery object (something they can't identify) and a surprise treasure (anything cool that wasn't on your list). Searching helps your kids tune in to their surroundings and notice the variety of life on any beach. When they're done, invite them to create a sand sculpture that incorporates their finds. (Be sure to have them wash their hands when they've finished.)