Tunnicliffe also competes at the highest level in CrossFit, appearing at the CrossFit Games in 2013, 2014, and 2015. Her best finish was 9th overall, in 2013. She has two first-place event finishes at the Games: "The Beach" in 2014, and "Sandbag 2015" the following year.
Anna Tunnicliffe was born in Doncaster, England. Her parents owned a yacht when she was a child and introduced her to sailing. Anna moved to Perrysburg, Ohio, in the United States, with her family at the age of 12. She attended Perrysburg High School and joined the North Cape Yacht Club, racing Optimists and other small boats for the next five years. In 1999 she began sailing the Laser Radial. Her first event in this boat was at the Leiter Cup in Detroit, Michigan. Despite her small build she advanced to the Smythe Finals for her area, where she was the only woman sailing. She participated in cross country, swimming, and track at the varsity level. In her senior year she won the district track championships in the 800 meters, setting a new high school record of 2 minutes 17.56 seconds. After choosing sailing over track, she decided to go to the Old Dominion University to study and sail.
In January 2014, Tunnicliffe announced her retirement from Olympic Sailing after 12 years of competition. She continues to pursue her professional CrossFit career.
Tunnicliffe helped to bring four national championships to ODU, including the ICSA Women’s National Championship and three ICSA Women’s Single-Handed championships. She competed as an A division skipper for the women’s team and B division skipper for the co-ed team during her junior year, and as an A division skipper for both teams as a senior. In her sophomore through senior years, Tunnicliffe was awarded women’s team all American status; she earned co-ed all American status in her senior year. For every year the Quantum Sailor of the Year award (recognizing the top American college female sailor) was given, Tunnicliffe was a finalist. She was a runner up her junior year, missing 1st by 0.02 points, and won in her senior year. She was one of three finalists for the ICSA sportsmanship trophy.
Tunnicliffe is ranked 1st in the world for the women's singlehanded dinghy, the Laser Radial.