Pacific White-sided Dolphins (Lagenorhynchos obliquidens)
These three were just beginning to surface. (The individual at the bottom of the photo is still under water.) Those are bubbles streaming from their blowholes.
The next image shows the same three coming into view.
Note the short beak and the large, curved, bicolored dorsal fin. Pacific White-sided Dolphins are ~2.5 meters (~8 feet) long.
In the next photo only the tip of the dorsal fin is above the water. You can also see the narrow gray stripes running from the head towards the tail.
It's difficult to predict and time a dolphin's leap. I tracked this one under water and was lucky when I pressed the shutter at the right moment.
Pacific White-sided Dolphins are endemic to the North Pacific Ocean. They occur from the Bering Sea and Sea of Okhotsk to the Gulf of California and Taiwan. Highly sociable, they are often observed in large groups (into the thousands). We were fortunate to encounter quite a few near Cordell Bank on 2 September 2012. These photos were taken as the dolphins came in to ride the bow wave of the New Sea Angler.
From the Field Guide to Marine Mammals of the Pacific Coast (Allen, Mortenson, and Webb 2011):
"Exuberance is the Pacific White-sided Dolphin's hallmark. The lag [short for Lagenorhynchos] is one of the liveliest dolphins in the northern Pacific, leaping clear of the water, belly flopping, somersaulting, and speeding in and out of the water in a rooster tail of spray. The lag will often approach vessels, sometimes unexpectedly, and ride the bow waves."