This child was definitely having a ball of a time at the annual Sydney Festival yesterday, while playing in a free art installation called The Beach.

Created by New York-based design studio Snarkitecture, the work brings a twist to a beloved summertime activity, allowing visitors to plunge into a 60m by 23m "sea" made of 1.1 million recyclable plastic balls.

"Jump in, swim around or just lie on top for that contemplative floating-on-water feeling," Snarkitecture's Ben Porto told the Sydney Morning Herald.

Those feeling less adventurous can opt to lounge on deckchairs put up on the synthetic white "sand" surrounding the ball pit.

The Sydney Festival is a celebration of art and "big ideas", according to its official website. This year's edition, which runs from today to Jan 29, features more than 450 performances by more than 1,000 theatre, dance, music, circus and art practitioners.