Manager and assistant coach Leyton Watson said his players had been in top form in the build- up to the nationals.
"The boys have been training hard and all have had some solid performances in individual tournaments leading up to the nationals, so they are excited about the opportunity to push for a three-peat," he said.
"The boys are very focused and committed to giving their very best.
"There has been lively competition for places in the final six, which has raised the fitness levels and quality of play from all members of the squad," Watson said.
The national tournament began in 1985 and has traditionally been dominated by Auckland Grammar and Christchurch Boys' High School, with Westlake Boys' High School, Whangarei Boys' High School and Palmerston North Boys' High School also contending regularly.
Tauranga Boys' finished last out of 32 schools at their first nationals in 2003 and improved to second in 2011 before back-to-back wins in 2012 and 2013.
The rapid rise can be attributed to quality facilities and coaching.
The Carrus Corporation has helped the team get to Nelson.