Almost 800 people have stripped off at South Fremantle beach in Perth to record the world's largest skinny dip.

The event raised money and awareness for the Butterfly Foundation, a national charity representing those affected by eating disorders and negative body image.

The co-owner of a local restaurant that organised the event, Lorna Marns, said the large-scale skinny dip was about more than just getting your gear off for a good cause.

"It is an inspiring event providing the opportunity to cast aside concerns of body image and celebrate every body, no matter the size or shape," she said.

Ms Marns earlier said organisers were hoping for 1,000 skinny dippers, which would break the record held by New Zealand with 744 skinny dippers.

While falling short of their goal, they surpassed New Zealand's total with 790 dippers.

Guinness World Record is yet to confirm the record.

Paralympic swimmer and event ambassador Jessica Smith said the record attempt was a fantastic opportunity to promote much needed awareness about the seriousness of negative body image and eating disorders.

"Women and men of all ages are subconsciously and consciously pressured to conform to societal beauty and body ideals," she said.

"The constant barrage of negatives messages and images that we are fed via the media has fundamentally resulted in generations of people who believe they aren't perfect and therefore should hate who they are and the way they look.

"This event is an opportunity for people to join with their community and simply have fun, relax and promote positive body image by embracing their own bodies."