A world record skinny-dipping attempt bottomed out at Swanbourne beach yesterday, with the bid falling 73 people short of the Guinness Book of World Records mark of 744.

Cracks started to appear in The Naked Fig's Skinny-Dip record hopes when the beachgoers were confronted by cool weather.

But a late, rearguard action gathered momentum for the group, only for them to fall just behind the target.

The bid raised thousands of dollars for the Butterfly Foundation, which fights eating disorders and negative body image.

"Everyone was in great spirits," Fig Group co-owner Greer Marns said.

"The main purpose of the event was to promote positive body image and celebrate our health, wellbeing and diversity, so I think we certainly achieved that," she said.

"Over the last few weeks we have heard so many personal stories of locals being affected by negative body image. Many of those people took part today and embraced this event as an opportunity to confront their personal issues."

Paralympic swimmer Jessica Smith was the official ambassador and was thrilled that hundreds of people of all shapes and sizes took the opportunity to accept and embrace their bodies.

"There certainly was a lot of laughter, with participants feeling quite liberated," Ms Smith said. The group vowed to be back next year.