“I was scared all the way through and was just trying to get through it alive,” Tyson, 54, tells The Post. “I’m a scary guy but not when it comes to adventurous stuff.”

“One shark kept bumping me and I’m like, ‘What the hell do you want?’”

It’s all documented in “Tyson vs. Jaws: Rumble on the Reef” (Sunday at 9 p.m.), in which the former heavyweight champ spends a week-and-a-half in the Bahamas training to go face-to-face with the killer predators — helped by “ringman” Paul de Gelder, an Australian Navy diver who lost and arm and a leg in a 2009 shark attack.

“I said, ‘Listen, this is not a good time to make me feel confident in there, seeing this guy who’s got an arm and a leg missing,’” Tyson says.

It didn’t help that he doesn’t like water — “I’m scared of anything in the water — I won’t even put my foot in the water,” he says on Sunday night’s telecast. So, he’s prepped in stages for his eventual hands-on underwater experience. He first trains (with de Gelder) in a pool, using an animatronic shark, and then descends underwater in a cage, where he’s miked up for his reactions to the schools of sharks surrounding him.

“I was more nervous in the cage than I was outside the cage,” he says. “It’s so claustrophobic in there. But it got easier and the desire to do it more overcame me as well. After I went down the first couple of times I didn’t have that fear.”

He takes several underwater dives until he’s out of the cage and ready to actually touch a shark with his bare hands — in what’s called “tonic immobility,” where its nose is rubbed until it falls into a state of natural paralysis.

“That was fun,” he says. “I was looking forward to that. [The shark] felt like one big muscle. It was so powerful.

“I was looking forward to meeting a tiger shark but he never showed up,” he says. Maybe it was scared of  “Iron Mike’s” fierce reputation. “I would like to believe that,” he says.

Tyson is currently training for his eight-round, “Frontline Battle” comeback fight against Roy Jones Jr., available on pay-per-view Sept. 12 (9 p.m.) It’s his first fight in 15 years and viewers will glimpse him training for that in “Rumble on the Reef.”

“I’m trying to make a comeback and it’s pretty nerve-wracking,” he ways. “I felt that [the sharks] would give me an upper-hand in dealing with the fight.”

Still, he says that facing an opponent in the ring is still scarier than his underwater sojourn.

“It’s the ring, baby, the ring,” he says. “That gets me going. With the shark, it’s over real quick.”

But he says he might consider diving with sharks again some time.

“There’s a possibility, but it would have to be for a good cause,” he says. “I’m not a beach bum — I’m a concrete type of guy.”