Two kayakers in California had a lucky escape when a humpback whale breached the water and landed on their kayak.

The footage shows kayakers disappear under the mass of foam and waves as the whale hits the water near Monterey Bay's Moss Landing Harbor. 

The whale watchers surface within seconds, remarkably unscathed.

The incident was filmed by a passenger on a whalewatching trip, organised by Sanctuary Cruises, who posted it to their YouTube account.

"On our 08:00am Sanctuary Cruises whale tour, just outside the harbor in Moss Landing, two kayakers on a tandem kayak were almost crushed to death by a massive, near full-size humpback whale."

“We stopped to see a large aggregation of humpbacks feeding and carrying on with random acts of hijinks.

“There were also a lot of kayakers right in the middle of it all. Humpbacks were coming up next to and in the middle of many kayakers. It was amusing.”