POIPU >>  As a five-year lifeguard, Alohi Costa finds lots of things, both in and out of the water. Rings, sunglasses and cameras, to name a few.

“We find all kinds of stuff out there,” he said.

But a leg? That was a first.

It was during a swimming workout on a sunny, clear morning in late August, about 60 yards off shore in front of the main Pavilion at Poipu Beach, when he noticed a fin protruding from a reef. He dove about 20 feet down and grabbed it. Hold on. A little more than a fin here. Attached to it was an entire prosthetic leg, tucked into a little cave on a reef.

He knew, right away, it had to be the one reported lost in late July. A co-worker mentioned to him a visitor’s prosthetic leg had come off in the water and sank at Brennecke’s Beach.

He returned to surface, five-pound leg in his arms, and swam back to shore. He washed and rinsed it off. Other than some algae growing on the fin, it seemed fine.

“It was in pretty good condition,” he said.

Costa went to the log book kept by lifeguards that includes lost and found. There, under the filing for the lost limb, was the name Gleb Sapozhnikov and a phone number.

He called the man at his Portland, Oregon, home.

“I’m Alohi,” he said to the voice on the other end. “I recovered your prosthetic limb for you.”

A stunned Sapozhnikov was almost speechless.

“Wow, that’s amazing,” he said.

Incredulous is a good word to describe Sapozhnikov’s reaction, who was just about to file his insurance papers on the lost leg.

“I couldn’t believe it,” he said.

Sapozhnikov thanked him repeatedly and repeated how much he appreciated that Alohi found the leg and tracked him down.

“He was so happy I found it,” Costa said.

Sapozhnikov said it was July 23, the day before he and his family were scheduled to head home following a three-week vacation on Kauai, when the inconceivable happened. He was swimming with his older son about 8 p.m., getting a few final runs in, off Brennecke’s Beach while his wife and two children were on the shore.

It was then his new, $8,000 prosthetic, titanium leg, came off.

“A wave came and ripped it off me,” he said.

It was gone, sinking rapidly into the deep. And since it was dark, there was no hope of recovering it then.

“No way could I find it,” Sapozhnikov said.

The leg was designed specifically for the water, completed in June, in time for the family’s Hawaii trip. Sapozhnikov can extend the foot to 180 degrees, put on a fin and swim. It worked well in his one trial run.

The swimming leg was necessary following a January 2013 motorcycle accident. Sapozhnikov spent a month in the hospital, endured six surgeries and had to have his right foot amputated.

“I’m glad it wasn’t worse,” he said.

Always active, he went through physical therapy, learned to use a prosthetic leg, and resumed biking, skiing, body surfing and swimming.

“I was happy to be at the same level as before the accident,” he said.

A family trip to Kauai was scheduled and Sapozhnikov was ready with his regular prosthetic leg for walking and his swimming leg. All went well on the island until that wave that sucked the leg right off him, which he didn’t believe could happen. The prosthetic leg has a ratchet system and suctions to his real leg.

“I thought it would be hard to come off in the water,” he said.

His son swam to shore and told his mom she needed to go to the condo and retrieve his dad’s walking leg. When she returned with it, Sapozhnikov crawled to the beach and put it on.

Because the family was scheduled for a flight home in less than 24 hours, Sapozhnikov had little time to search for his leg. He left his name and number with police, a local surf shop and the lifeguard stand in case someone, somehow, found it. It seemed hopeless, but that message with the lifeguards would prove critical.

Sapozhnikov is a bit of a bulldog when need be, someone who remains optimistic and hopeful.

“When I lose something, I try to follow all possible avenues to try to retrieve it,” he said.

His perseverance paid off.

In the following weeks, Sapozhnikov sent a prepaid box to Costa, who wrapped, packed and mailed it. A few weeks later, the leg arrived at the door of Sapozhnikov’s Portland home.

The leg was, it turned out, much worse for its month under water then it seemed after first glance. Sapozhnikov’s prosthetist examined it and said anything titanium and aircraft grade aluminum was as new, but everything else suffered to varying degrees.

— There was wear on the plastic due to abrasive action of rocks and sand at the sea bottom (plastic still usable though).

— The mechanical assembly responsible for leg release was made out of regular aluminum and is now one solid piece that most likely has to be thrown away and replaced.

— Spring action in the ankle is blocked — but most likely can be brought back. The foot itself isn’t in too bad of shape.

— The bolts and adjustment screws, made of stainless steel, were badly rusted.

Still, Sapozhnikov was very appreciative the leg was returned to him. He noted that he has lost $200 cellphones and never saw them again.

“He’s a Good Samaritan,” he said of the lifeguard. “It’s amazing somebody would do this for me.”

“It’s sort of a miracle,” he added.

Costa said he was simply glad to return a lost limb and help someone out. In his years of lifeguarding, he couldn’t imagine finding something more important.

“It’s kind of miraculous,” he said.