One of them brought home a special prize.
More than 1500 high school students from 50 countries were invited to the event.
Five of them represented Hawaii. Senior Aloha Yoza and juniors Diana Cabrall and Noelle Owen hoped their project would get some recognition.
"It's a machine to simulate tides using a water bridge and circuitry. So, can flip a switch and move one tank up and the other down. It shows high tide and the inverse low tide," said junior Noelle Owen.
Aloha Yoza did the problem solving, and Diana Cabrall and Noelle Owen built the structure.
"So, working with the team really allowed us to bring all our expertise together and create a project," said senior Aloha Yoza.
Their hard work earned them the National Oceanic Atmospheric Administration award at the competition.
"It was totally exciting to go because it was a really good project, new and innovative. It's never been done before, so we we're super stoked to give it to them," said junior Diana Cabral.
Sophomores Lindsay Fujimoto and Sarah Tamashiro also made the trip to Reno, with their project on using one of Hawaii's abundant natural resources for Bio Fuel production.
"We could use the algae energy for us and we become more independent," said sophomore Lindsay Fujimoto.
Even though the sophomores didn't bring home one of the awards, the girls say it was great to represent Hawaii at the international competition.
"It was a big accomplishment because we really wanted to go this year and we're thankful for everyone who helped us along the way," said sophomore Sarah Tamashiro
It wasn't only a successful school year for these Priory students. Their teacher Michael Grech, took home an educator award.
St. Andrew's priory is the only Hawaii team, to win the "Discover Your World with NOAA" award. It's a one-week, all expenses paid trip, to any NOAA site.