'Surf passage' is one of the most iconic and formidable parts of Navy SEAL training - here's what it looks like

The US Naval Special Warfare Center is very close-mouthed about how it trains future Navy SEALs.

Photos and videos are rare, and oftentimes the only information available to the public is through firsthand accounts of those who've endured one of the world's most arduous training regimens.

But there is at least one type of training into which the Navy has given the public a glimpse: surf passage, where small teams of SEAL candidates paddle inflatable boats through waves crashing into San Diego's Silver Strand.

"Surf Passage is one of our more iconic training evolutions," Lt. Trevor Davids, a public affairs officer at the Naval Special Warfare Center, told Business Insider.

"It's first addressed within the first week of Naval Special Warfare Orientation," Davids said, adding that candidates from both the Special Warfare Combatant Craft Crewman and Basic Underwater Demolition/SEAL programs participate in the training.

Here's what they do: