The Shadow Swim was an unprecedented 23-mile marathon swim from Clearwater Beach to St. Pete Beach in Florida, U.S.A. on 6 December 2014 by Lisa Hertz, a 28-year-old American marathon swimmer and English school from Winter Haven High School in Florida.
Lisa Hertz has completed marathon swims including the first double crossing of the Assawoman Bay/St. Martins River channel from Ocean Pines to Ocean City, 6.7 miles in 2 hours, 55 minutes, the Swim Miami 10K, the Swim Charleston 12 Mile Swim, and Tri-Floyd's 8 Mile Swim. Hertz was the winner of the women's division of 2013 Swim Around Charleston and is the 2013 women's winner and current record holder of the Tri-Floyd 8 Mile. Hertz swam for Franklin and Marshall College between 2003 and 2007, competing in sprint freestyle and backstroke events. She was also the 2008 recipient of the Cynthia Earley Educational Foundation scholarship and competed in the Chesapeake 4.4 Mile Bay Swim (2008-2010) and the Tampa Bay Frogman Swim (2013, 2014). She finished second in the 2014 Tampa Bay Marathon Swim in 12 hours 46 minutes as well as the 23-mile Shadow Swim.