The visiting team had eaten hotdogs after the match, before heading back to Kokiri Lodge where coaches set about building a bonfire for the evening's entertainment.
While that was under way, James and three mates ventured down to the Arnold River.
On the way back, he missed the turn off to camp and was soon lost and disoriented.
"I kept walking, calling out friends' names, but I didn't know where I was. So I stayed by the river," he said yesterday.
It wasn't until tea-time, when team coach Phil Kennett realised a boy was missing, that a full scale search was launched.
Two search and rescue teams, two search dogs and a police dog hunted through the night.
The Solid Energy Rescue Helicopter and pilot with night vision gear were also called in to help.
Meanwhile, James - who was wearing only shorts and a singlet - moved into survival mode.
"When it started to get dark, I found a bunch of ferns and pulled them together to keep me warm," he said. "I was nervous and scared that no one would find me."
His spirits were raised when a helicopter flew overhead, but it was too dark to see him.
"I was scared I'd not make it. But when I saw the chopper a few times, it made me happy to know they were trying really hard to find me. I couldn't stop shaking, I was so cold.
"I was feeling really guilty and thinking 'mum's going to have a go at me'. I knew cops would wake her up."
Greymouth police had indeed phoned Ms Boyce at her Christchurch home at about 9pm on Saturday.
"They told me James was missing and I just burst into tears," the 37-year-old retail assistant said.
"I phoned my parents in absolute tears, saying 'we have to go'. It was a very quick trip to Greymouth."
When she arrived at around 1am, the search was ongoing.
There was still no sign of James, and coach Mr Kennett admitted: "We all feared the worst."
By now, James had decided to stay put, and try to keep warm in the undergrowth on the riverbank.
As dawn approached, he heard a dog barking and getting closer.
"It came right up to me and lay down right beside me," he said. "I saw a couple of torches and asked who they were.
"They said they were search and rescue and I was so relieved they found me. I tried to stand up but my legs were wobbly like jelly because I was so cold."
The rescuers warmed him up and they walked the 3km back to Kokiri Lodge at 5am.
He was greeted by an "overwhelmed" mother and surrounded by his waiting teammates.
"When I saw him I just wanted to hold him," Ms Boyce said. "It was the longest night of my life."
The youngster is planning a walkathon to raise money for search and rescue, because, as he puts it: "They saved my life."
