Before you go, we thought you'd like these...  Bo Derek makes a splash!  The 59-year-old actress looked absolutely ageless as she took part in a 3000 meter open water swimming marathon in Greece on Saturday.  WATCH: Bo Derek Talks 'Sharknado 3,' Opens Up About Her Relationship With John Corbett  Derek had no problem showing off her fit physique in black bikini bottoms and a hot pink rash guard as she walked along the beach.  The 10 star later ditched the backpack and flip flops as she prepared to enter the water.  WATCH: 'Sharknado 3': On Set With Ian Ziering, Bo Derek and a Pregnant Tara Reid!  While the 3000 meter race might seem a little daunting, Derek is no stranger to the water. A southern California native, Derek's a big fan of swimming -- and even credits it for her age-defying figure.  "I have to admit part of my compulsion to do this swim was I want to eat like Michael Phelps," she told ET in 2013. "I mean if you look at all the list of what we can do for exercise and how many calories it burns, swimming's always at the top. So that was one of the reasons I took up swimming again."  "Swimming is good, swimming is really good," she added. "I do recommend it."  PHOTOS: Bo Derek through the years  Bo Derek through the years  Bo Derek through the years  PHOENIX, ARIZONA - APRIL 09: Bo Derek arrives at Muhammad Ali's 22nd Celebrity Fight Night held at JW Marriott Desert Ridge Resort & Spa on April 9, 2016 in Phoenix, Arizona. (Photo by Michael Tran/FilmMagic)  AACHEN, GERMANY - JULY 12: Bo Derek attends the media night of the CHIO 2016 on July 12, 2016 in Aachen, Germany. (Photo by Andreas Rentz/Getty Images)  NEW YORK, NEW YORK - MARCH 15: Actors John Corbett and Bo Derek arrive at the premiere of My Big Fat Greek Wedding 2 and walk the Windex blue carpet in New York City, on March 15, 2016. (Photo by Mike Coppola/Getty Images for SC Johnson)  NEW YORK, NY - MARCH 15: Bo Derek attends the'My Big Fat Greek Wedding 2' New York Premiere at AMC Loews Lincoln Square 13 theater on March 15, 2016 in New York City. (Photo by Donna Ward/Getty Images)  NEW YORK, NY - MARCH 15: Actress Bo Derek attends the 'My Big Fat Greek Wedding 2' New York premiere at AMC Loews Lincoln Square 13 theater on March 15, 2016 in New York City. (Photo by Jim Spellman/WireImage)  BEVERLY HILLS, CA - JANUARY 08: (L-R) Actors John Corbett, Bo Derek, Sharon Stone, and Chris Noth attend Ketel One Vodka Celebrates Excellence In Cinema with 'Spotlight' Pre-Golden Globe Celebration at Bouchon on January 8, 2016 in Beverly Hills, California. (Photo by Imeh Akpanudosen/Getty Images for Ketel One)  BEVERLY HILLS, CA - NOVEMBER 7: Bo Derek and John Corbett attend the WildAid 2015 on November 7, 2015 in Beverly Hills, California. (Photo by JB Lacroix/WireImage)  BEVERLY HILLS, CA - NOVEMBER 7: Bo Derek attends the WildAid 2015 on November 7, 2015 in Beverly Hills, California. (Photo by JB Lacroix/WireImage)  NEW YORK, NY - JULY 14: Actress Bo Derek attends the 'Sex&Drugs&Rock&Roll' And 'Married' New York Screenings at SVA Theater on July 14, 2015 in New York City. (Photo by Mark Sagliocco/Getty Images)  BERLIN, GERMANY - SEPTEMBER 05: Bo Derek attends 'Sharknado 3' Premiere in Berlin on September 5, 2015 in Berlin, Germany. (Photo by Sebastian Reuter/Getty Images)  NEW YORK, NY - JULY 14: Actors John Corbett and Bo Derek attend the 'Sex&Drugs&Rock&Roll' And 'Married' New York Screenings at SVA Theater on July 14, 2015 in New York City. (Photo by Mark Sagliocco/Getty Images)  MONTE-CARLO, MONACO - JUNE 18: Bo Derek attends the 55th Monte Carlo TV Festival Closing Ceremony and Golden Nymph Awards at the Grimaldi Forum on June 18, 2015 in Monte-Carlo, Monaco. (Photo by Tony Barson/FilmMagic)  MONTE-CARLO, MONACO - JUNE 16: Bo Derek and Eric Close attend the 55th Anniversary Party at the Monte Carlo Beach on June 16, 2015 in Monte-Carlo, Monaco. (Photo by Tony Barson/FilmMagic)  MONTE-CARLO, MONACO - JUNE 18: Bo Derek attends the 55th Monte Carlo TV Festival Closing Ceremony and Golden Nymph Awards at the Grimaldi Forum on June 18, 2015 in Monte-Carlo, Monaco. (Photo by Tony Barson/FilmMagic)  MONTE-CARLO, MONACO - JUNE 15: Jury member of the 55th Monte Carlo TV Festival, Bo Derek attends a photocall on June 15, 2015 in Monte-Carlo, Monaco. (Photo by Tony Barson/FilmMagic)  US actress Bo Derek poses for a photocall during the 55th Monte-Carlo Television Festival on June 15, 2015, in Monaco. AFP PHOTO / VALERY HACHE (Photo credit should read VALERY HACHE/AFP/Getty Images)  US actress Bo Derek waves as she poses for a photocall during the 55th Monte-Carlo Television Festival on June 15, 2015, in Monaco. AFP PHOTO / VALERY HACHE (Photo credit should read VALERY HACHE/AFP/Getty Images)
Bo Derek showed off her famously fit figure during a marathon swimming race this weekend. She looks incredible.