Chapter 12: At Sea
When the chapter starts you will be driving a boat. Drive it to the back of the main island. There are three dolphins in the water here.
We will start with the one closest to the tower island.
#1 - Far out in the water (at the back of the tower island) you will see 3 rocks. Near those rocks is a dolphin (to the left of the rocks when you come from tower island).
#2 - When you drive in a straight line between #1 & #3 you'll find this dolphin. At the back of the large island far out in the water. He is swimming around a lot, so his location varies slightly. Sometimes he is further out, sometimes closer to the island.
#3 - Near the island with the sunken pirate ship.
Basically, you just need to drive in a straight line and should get all 3. Because they are swimming around a little bit their location varies. They are always in the same distance to each other, but sometimes they are further out in the water, sometimes closer to the main island.