To take a trip under the water go to free session mode. Here you can
choose any person or board you want. Then go to Tavarua island. Go
around the island on the right side to where the buoys intersect with
the island. Go out  past the buoys and back in to draw the shark out.
Then go out a second time to have the shark get you. here the shark
should carry you under the island where you can swim around.        (no
waves go under here)