More than 500 pupils and staff gathered at South Beach, Saltwater Creek and the Crows Nest yesterday as part of the school's Pride 2012 programme.
It was the idea of senior pupils who wanted to engage with the community and take part in voluntary work.
Co-ordinator and Year 13 pupil Lucy Godwin said students were tasked with cutting flax, clearing pathways, cleaning up rubbish and weed spraying.
"It's about taking pride in our community; we're giving something back. It's a good experience for the students to do some volunteer work."
It is the first time the whole school has dedicated a day to voluntary work and another one is planned for next year.
Teacher Peter Johnson said staff were proud of what the senior students had achieved.
"They wanted to leave a mark when they left school; it's meant they have set a target for next year's senior students."
- The Timaru Herald