A boat from Harbor Breeze Cruises came across a mother humpback and her calf just a few miles from the coast of Long Beach on Tuesday.
The cruise company posted a video of the encounter on Facebook. It shows the whales breaking the surface a few times and then smaller creatures swimming near them.
"These whales were heading up the coast until a pod of Pacific white-sided dolphins got them fired up and playing around the boat," Harbor Breeze Cruises wrote in the post.
The tourists can be heard on the video cheering and wowing with excitement and astonishment at the sight of such majestic beauty.
Adult humpback whales, which are endangered, weigh up to 40 tons and are up to 60 feet long.
"Humpback whales are a favorite of whale watchers, as they are generally found close to shore and are commonly active at the surface, for example breaching (jumping out of the water), or slapping the surface with their pectoral fins and tails," according to NOAA Fisheries. "Humpback whales filter-feed on small crustaceans (mostly krill) and small fish, consuming up to 3,000 pounds of food per day."
Humpbacks and other whales face potentially deadly threats, such as collisions with ships and entanglements in fishing gear.
Pacific white-sided dolphins weigh between 300 and 400 pounds and are between 5 and 8 feet long. As the video shows, they are extremely playful and are often seen jumping out of the water and swimming near the bows of vessels.
"Pacific white-sided dolphins in the United States are not endangered or threatened, but they are protected under the Marine Mammal Protection Act," according to NOAA Fisheries. "A primary threat to Pacific white-sided dolphins is entanglement in fishing gear, such as gillnets and trawls.