Thirty-nine New Zealand athletes are on Wednesday boarding a plane for Berlin to compete in the Special Olympics.

For many of the competitors - who have intellectual disabilities - the quadrennial event is their first time away from their families, as they chase coveted gold medals and life experiences.

Swimmer Jesse Williams was competing in his first games, although he was a veteran sportsman. He looked fit and lithe as he talked to RNZ beside a Palmerston North swimming pool before a training session.

Previously a long-distance swimmer, he was entering the 25- and 50-metre freestyle events. He expected to swim the shorter distance in 16 seconds and the longer one in the 30s.

To get there, coach Carla L'Huillier put him through his paces twice a week, and he trained outside of this - in the pool and in the gym.

Jesse Williams' coach Carla L'Huillier says he has the ability to go fast. Photo: RNZ / Jimmy Ellingham

In swimming terms, the 37-year-old, who has Down syndrome, is a veteran.

"I've been swimming for 23 years now. It's good exercise. I get fit."

He was definitely that and L'Huillier, travelling to Germany as the New Zealand team's swimming coach, rated his chances.

"He's one of our fastest guys. We've just got to keep him on track. He doesn't train very fast, but he races really well, which is one of the good things about him."

Special Olympics were about more than sport, L'Huillier said.

"It's how much the athlete grows because they go away and they've really got no idea what it's going to be like, and suddenly they're in a stadium with 7000 other people.

"It's really cool. It's like the Olympics. You come in and you're waving and everyone's cheering for New Zealand."

Ten-pin bowler Josh Ryan has experienced that before. These are the Palmerston North 41-year-old's fourth games.

Berlin is Josh Ryan's fourth Special Olympics. He's part of the ten-pin bowling team. Photo: RNZ / Jimmy Ellingham

"It's the world Summer Games. In bowling, there are four people."

After regular weekly practice at a local lane, he said his form was "really good".

Three-a-side basketballer Hayden Wilson was a man of few words off the court, but on it he showed off the skills he had honed after months of hard work, including regular dribbling practice on his Palmerston North driveway.

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Hayden Wilson's part of New Zealand's three-a-side basketball team. Photo: RNZ / Jimmy Ellingham

The athletes have each raised thousands to get to Berlin, and Wilson had spent hours manning sausage sizzles between training to get him there. Step-father Ron Smith said the experience helped Wilson come out of his shell.

"It's had a big impact on his life. It's given him confidence and the ability - because of his autism - to talk to strangers.

"I also believe that when he goes to Berlin, when he comes back he's going to be a really changed person."

The Special Olympics opening ceremony, to be televised globally, is on Sunday, 19 June, New Zealand time.

This story was first published by RNZ