Shawn Stamback and three friends were scuba diving last weekend off the coast of California exploring a coral reef when they were nearly swallowed by a pair of nature's biggest beasts, the humpback whale.

The massive whales lunged out of the water with their huge jaws open as they chased a school of fish right next to the swimmers.

"I still don't know how they got that close to us without us knowing," Stamback, 39, of San Louis Obispo, told ABCNews.com. "I was probably like six to eight feet away."

"The first thing that went through my head was that I didn't want to get swatted by the tail because you see two whales that are moving away from you and you know how long they are," he said.

Stamback, the owner of Slodivers, a charter scuba diving company, and his three fellow divers were in between dives Saturday morning off Morro Bay in central California when Stamback and another diver decided to dive back in to snorkel.

After a few minutes in the water the two men saw a swarm of fish shoot up to the ocean's surface. Not far behind them, looking for their next meal, were the two humpback whales.

"I made a bullet to the boat to try to get out of the water," Stamback said. "I was pretty much in shock. You're in survival mode."

Both Stamback and his fellow diver made it back to the boat safely, where they were greeted by their two friends on board who had filmed the close encounter.

"Even the guys that weren't in the water were pretty shook up about it," Stamback said. "We laughed it off, but we were all shook up."

"You're going to have to do more to clean that wetsuit," one of the men can be heard saying in the video, which has been viewed more than one million times on YouTube.

Stamback says he and his friends were just out to explore the coral reef in the area and had no intention of looking for whales. In fact, there were no whales anywhere to be seen in the water, a reminder, he says, to expect the unexpected when in nature.

"You don't go looking for trouble like that," Stamback said. "If you're a scuba diver, everything you do is planned, but you're out in the wild so you can only plan what you have control of."

"When something like that happens, that's you're reminder that you're out in the wild," he said.