How Fast Can Dolphins Swim? Speeds of Common Species

How fast do bottlenose dolphins swim?

The common bottlenose dolphin, the best-studied species, usually travels at 5–11 km/h (3–7 mph), a pace it can keep up for hours while searching for food or moving along a coast. When it needs to, it can accelerate to bursts of around 29–35 km/h (18–22 mph), but only for short spells, such as the final rush at a fish or a dash away from a shark.

Dolphins are also remarkable at accelerating. In one aquarium study, a Pacific white-sided dolphin went from about 18 km/h to 31 km/h (5.0 to 8.7 m per second) in just 0.7 seconds, using only a few strokes of its tail. For comparison, even the fastest human swimmers average under 9 km/h (5.6 mph) over a 50 m freestyle sprint, a speed a dolphin can hold all day.

How fast are other dolphins and porpoises?

Speeds have been measured reliably for only a few species, and many published figures are estimates. These are the most commonly cited:

The orca is generally regarded as the fastest member of the dolphin family, with a long, muscular body built for powerful sprints. Dall’s porpoise of the North Pacific, often called the fastest small cetacean, throws up a distinctive “rooster tail” of spray when it races at the surface. Sleek oceanic species such as common and spinner dolphins are fast too, but good measurements of their top speeds are scarce.

Measured speeds versus sailors’ stories

Old accounts often credited dolphins with very high speeds. Many came from dolphins riding the bow wave of a moving ship. In that position the dolphin is pushed along by the pressure wave in front of the hull, so it can keep pace with a fast vessel while barely beating its tail.

Such reports led to a famous puzzle. In 1936, the British zoologist James Gray calculated that dolphin muscles could not produce enough power to swim as fast as people claimed unless their skin had some special way of reducing drag. This became known as Gray’s paradox. In 2008, a team of engineers filmed two trained bottlenose dolphins swimming through a curtain of tiny bubbles and measured the force of each tail stroke: about 90 kg (200 lb) of thrust, roughly ten times what Gray had assumed. Dolphins are simply far more powerful than he thought, and no magic skin is needed.

Bow riding, wave riding and porpoising

Dolphins save energy whenever they can. Besides riding the bow waves of ships, they surf in boat wakes, in breaking waves near the shore and even in the pressure waves pushed ahead of large whales. Short-beaked common dolphins are especially fond of this.

At high speeds, dolphins often leap clear of the water in a series of low arcs, a movement called porpoising. Air offers far less resistance than water, and in 1980 the researchers Au and Weihs showed that above a certain speed, jumping actually costs less energy than staying at the surface, where waves add extra drag. Porpoising also lets the dolphin breathe without slowing down.

What makes dolphins such fast swimmers?

Several features work together. The body is a smooth, torpedo-shaped spindle with no external ears or hair to cause drag. The skin is smooth and constantly renewed, so it stays free of fouling. The powerful muscles of the tail stock drive the flukes up and down, and the flukes themselves act like a pair of underwater wings, producing thrust on both the upstroke and the downstroke. The flippers and dorsal fin steer and stabilize.

Dolphins also swim efficiently by choosing their depth. When traveling, they often stay a little below the surface, avoiding the extra drag of making waves, and rise only briefly to breathe.

Dolphins versus other fast sea animals

Dolphins are quick, but they are not the fastest animals in the sea. The shortfin mako shark is generally considered faster in a sprint; see What is the fastest shark? Large predatory fish such as tunas and billfish are also built for speed, although many popular figures for them are exaggerated. For a broader ranking that covers land, air and water, see our list of the fastest animals.

To learn more about the dolphin behind most of these measurements, visit our profile of the common bottlenose dolphin.