The Invercargill school had been looking for a competition to enter after the Highlanders First XV competition was scrapped last month.
It was faced with entering the Southland under-18 competition, playing in a lower grade Southland competition, in which it would play against senior sides from clubs around Southland, or playing in the Dunedin colts grade. Southland does not have a colts grade.
Otago Rugby Football Union community rugby manager Richard Perkins confirmed the school side would front in the competition.
Otago Boys' High School has also entered the grade this year. The two schools were the only sides to win the Highlanders First XV competition in its six years in existence.
Perkins said Southland Boys' would provide a travel subsidy for teams to travel and play in Invercargill.
The Invercargill-based school is believed to have secured sponsorship to pay for the travel of teams heading south.
Southland Boys' High School coach Jason Dermody could not be contacted yesterday.
He had previously told the Otago Daily Times he wanted his side to play in the colts grade as it was a high standard of rugby and the travel was not a burden.
He did not want want to play in the Southland under-18 grade as the first XV would have to play sides from the same school while he did not want his younger players to take on older men in a lower grade Southland competition.
The division one colts grade has 11 teams this season while there are nine teams in the junior colts grade.
The competition starts on April 18. The Otago-wide premier schools competition starts the following week on April 25.
