New York City firefighter Richard Wilde made the ultimate swimmer’s pilgrimage, plying all 24 miles of the English Channel.

“I couldn’t believe I made it,” said Wilde, 43, who swam competitively in high school and college. “It was pretty rough going there for many hours.”

The water did not exceed 63 degrees during the 12-hour, 22-minute swim Monday across the Strait of Dover from Dover, England, to Wissant, France. He never alternated his stroke, going freestyle the whole way.

Wilde wore a bathing suit, a swimming cap and goggles. The Channel Swimming Association, which runs the challenge, disqualifies swimmers who wear wet suits, but they are allowed to eat, drink and coat their skin with grease to maintain energy and keep warm.

“Hot tea, bananas, hot chocolate and gel packs,” Wilde, who has been a lifeguard in Saltaire on Fire Island for 28 years, said Friday of his midswim diet. “About every 45 minutes or so, I would take a break for about 15 seconds and grab something to eat quick.”

The water was cold, he said, and he had to battle the strong current and deep fatigue. He willed himself to keep plowing along, hour after hour.

As part of the challenge, a two-man fishing crew and Channel Swimming Association official were alongside Wilde in a boat, acting both as witnesses and as transportation to get back to England once he reached the shore of France.

Fellow Saltaire lifeguard Catherine Darcy, 20, who was studying abroad in Dublin with the College of the Holy Cross at the time, joined the crew as Wilde’s lifeguard. Darcy, who is from Bay Shore, was in charge of bringing Wilde his drinks and snacks during the swim as well.

“She’d actually just throw them in the water and I went out to get them,” Wilde said.

When he completed the crossing, he climbed into the boat and got warm as quickly as he could.

Wilde first made his reservation to swim across the channel with the Channel Swimming Association three years ago.

As preparation, he’d been swimming in colder water and participating in long-distance open-water races. He currently holds the record for completing the most swims in the Maggie Fischer Memorial Great South Bay Cross Bay Swim from Fire Island to Bay Shore, finishing the 6.2-mile journey 15 times between 1999 and 2015.

Before competing in those races, Wilde was a swimmer at Hauppauge High School and captain of the Queens College swimming and water polo teams.

For Wilde, making it across the English Channel is more than his greatest swimming accomplishment. It’s the fulfillment of a lifelong dream.

“I’ve wanted to do it for a long time,” he said. “I probably learned about the channel when I was 13.”

This isn’t the end for Wilde, either.

“There’s a lot of big swims out there to do,” said Wilde, currently a Brooklyn resident. “Next week I’ll be back on the beach, swimming.”