What fun this was! I folded these two water balloons this morning. This simple design for “Inflatable Origami Water Balloons” is on the Internet. There was even a video. http://www.origami-instructions.com/origami-water-balloon.html
The online instructions were quite good – though sometimes, it was assumed you knew to turn the design over before folding each of the corners upwards.
Then as instructed, I blew air into both finished designs then filled one balloon with water – perhaps too much because it fell apart. So, I filled the second balloon with just a little water and it indeed became a water balloon for a few minutes before the paper began to dissolve. This would be great for kids to learn and just at my folding level.