"I was kind of scared at the final camp because there was a lot of competition with people from all over New Zealand trialling for these spots," Roberts said.
"There were people there I have played against and in Trans-Tasman with last year, so I was a little bit worried about my place in the team and whether I would make it. Luckily, I made the cut down to 12, which I am extremely stoked about."
Roberts described the final selection camp as brutal.
"On day one and two a lot of the focus was on fitness and puck skills. We did a lot of tests involving underwater breath holds and how fast we can do 16 lengths underwater, with rests in-between.
"The last two days we played against the under-23 New Zealand men's team and that was amazing but also so difficult. I liked it that we were allowed to have a game against them. We also focused on set plays, whiteboard tactics, going through the playbook, just seeing how we can improve ourselves and nutrition."
Two years ago New Zealand under-19 won the world championship title so repeating that feat was a goal for Roberts and his teammates.
"The last team had some Tauranga Boys' College students in Ben Richards and Keegan Thompson and our New Zealand coach Kendrick Knowlson is the coach of the Tauranga Boys' team.
"They won the gold two years ago, so hopefully, we can go back to back with all the training we have been doing leading up to this event and smash the Canadians and Columbians. I am pretty psyched up to do it."
Underwater hockey is still very much a minor sport in this part of the world, but in the five years, Roberts has been involved since joining from swimming he has seen a major increase in numbers.
"When I started in Year 9 there was no junior team at Tauranga Boys' so I went straight into the senior team. But when I got into Year 12 we had more than enough juniors, and I think we had nearly 20 trialling for the junior team.
"It was the first time we had to have a trial for the junior team. Going to secondary school nationals now you can see how many more people are involved. I am glad the sport is getting way bigger than what it was."