When chased by a speedboat, Dolphins have been clocked at speeds of 26.3 km/hr, which they maintained for about 1500 meters, leaping constantly. Energetic studies have shown, that the most efficient travelling speed for Dolphins is between6.0 - 8.2 km/hr. There have been reports of Dolphins travelling at much higher speeds, but these refer to Dolphins being pushed along by the bow wave of a speeding boat. They were getting a free ride. It is possible that Dolphins can reach speeds over 15 knots during very short bursts (like in preparation for a high jump), but they can't maintain that speed.