A version of tag in the deep blue sea.
To try and not get turned into a submarine
Designate the playing field (the ocean). Choose 2-3 taggers- they are the scuba divers. The rest of the children are the boats. If a scuba diver catches a boat- the boat gets pulled under the sea and becomes a submarine. So if one of the kids get tagged, they lie down on their backs and lift one leg to create a submarine. They can be turned back into a boat if another child comes and sets their leg back on the ground. They then can join back in the game.
Make sure the kids are gently putting the leg of the other kids back on the ground.