Food was served in sand buckets. I didn't get a picture before people started digging in, but you still get the idea.
They played a variation of dodge ball, only with sponges and water.
Beach Ball Pinata.
His "Under the Sea" cake from Dewey's Bakery.
When all of his guests left he said, "This was the BEST BIRTHDAY EVER! Thanks, Mom!" and then gave me a giant hug and kiss on the cheek. Truly the best reward a kid can give their mom.