Former world champion surfer Shaun Tomson and actress Tanna Frederick will co-host the Fourth Annual Project Save Our Surf: SURF 24, a celebrity surfathon to benefit Santa Monica Baykeeper, Waves for Water, Inside the Outdoors and Tumelo Home Saturday and Sunday, Oct. 15 and 16.

Project Save Our Surf is an organization of surfers, celebrities, families and businesses that create initiatives in support of clean water both locally and globally.

Celebrity surfers expected to participate in the annual surfathon include Sam Trammell (True Blood), Tate Donovan (Damages), John Slattery (Mad Men), Jesse Spencer (House), Richard Burgi (Desperate Housewives), Chad Lowe (24), Gregory Harrison (One Tree Hill), Michael Munoz (Amazing Race), Zoe Bell (Death Proof), Pat Parnell (Fuel TV’s The Daily Habit), Chris Bruno (Dead Zone), Galen Gering (Days of our Lives), David O’Donnell (Air Force One), Peter Brinkerhoff (Daytime Emmy winning director), Preston Davis (Entourage), John Philbin (Point Break) and Kathy Zuckerman (Gidget).

Noted surfers participating include Jon Rose, Mary Osborne, Don Bigelow, Buttons Kaluhiokalani, Erin Edwards, Chuck Patterson, James Pribram, Courtney Conologue, Trae Candy, Jesse Faen, Jessie Timm, Dougie Tanaka Jr., Angie Reno and P.T. Townend.

The surfathon will involve 12 teams of 24 participants per team, with each person surfing for 45 minutes. Team members are encouraged to raise $500 per person with 100 percent of total donations going to charity.

Prizes will be awarded to the individuals and teams who raise the most money.

The event will also feature daytime activities for the whole family including live music, mural painting with Joanne “Art Miles” Tawfilis, guest speakers, yoga and eco-friendly exhibits.

The event is scheduled from 8 a.m. to 5:30 p.m. Oct. 15 and 16 at Lifeguard Tower 28, just south of the Santa Monica Pier (Ocean Park and Barnard Way) in Santa Monica.

The Celebrity Surfing Session will take place from 10:15 to 11 a.m. both days. The Pro Surfer Session will take place from 9:30 to 10:15 a.m. both days.