Having finished second both of the past two years, the club put in a dominant performance to claim the title in Christchurch at the weekend.
It accumulated 218 points to finish well-clear of second-placed South Brighton, which finished with 140.5. The win was St Clair's first since 2014.
``It was really good; it was a pretty comprehensive team performance,'' club chairman James Coombes said.
``It had been a couple of years since we had won the South Island title, so it was pretty pleasing for us to get over the line and win the title.''
St Clair picked up plenty of points across the team events, which Coombes said was pleasing as it showed good club depth. Among those were the Taplin relay, the pinnacle team event, which it won in five of the six grades.
Brothers Nathan and Max Wolf were among the top performers, as were Lucy Matehaere and junior Olivia Andrews, who came up an age-group to win several events.
Coombes said the club had a controlled structure in place which helped the athletes. This year for the first time it had appointed Brent Wolf to oversee the surf sports side of the operation. Before that, the club had someone responsible for life guarding, but no-one specifically directing the sporting side. It was hoped that would help the club continue to build on its success in the coming years.
The national championships were the next big event on the agenda. They will be in Christchurch beginning on March 16.
The junior club is heading to its national championships in Mount Maunganui this weekend with high hopes, having won the South Island title last weekend.
- Jeff Cheshire