This is a bottlenose dolphin. Forgive the motion blur and framing - these were taken whilst hanging onto a boat in a mask and snorkel being dragged along as the dolphins rode the bow wave of the boat. Its not the easiest way to take photos but it works - its also not particulalrly safe unless you and the boat-handler know exactly what you're doing (so don't try this at home kids - seriously). Dolphins often find humans too slow-moving in water to be interesting but enjoy playing with boats. In this situation the water was full of stingless jellies so we were also dealing with them bouncing off our faces as well as enjoying the show the dolphins put on.
As a side note its generally not a good idea to jump into deep water with dolphins or small whales as pelagic sharks often trail dolphins and they can be stimulated to attack by the different body signature of a human swimming among dolphins.