Deniz Kayadelen is a Turkish-German dual citizen, open water and ice swimmer, industrial psychologist, management consultant, author, and professional speaker. She made history as the first Turkish woman to compete in the World Open Water Ice Swimming Championships. Throughout her career, she has won six world championships, two European championships, one Guinness World Record, and the prestigious “Triple Crown” title—one of the most esteemed honors in open water swimming. In addition to her athletic career, she served for many years as a senior executive and consultant at Ernst & Young (EY), specializing in talent management and change management. She resides in Männedorf, Switzerland.

^{Deniz Kayadelen (AA)}

Deniz Kayadelen was born in Frankfurt, Germany. After her parents separated and her family faced financial hardship, she moved with her mother to Istanbul, Türkiye at the age of 11. She has stated that upon arriving in Türkiye, she did not speak Turkish and was mocked by classmates due to her accent. She experienced this period as a cultural shock and sought refuge in swimming. She began swimming at age six and continued her sport as a pool swimmer with Yeşilyurt Sports Club after relocating to Istanbul, later joining Bakırköy Ata Sports Club. She describes herself as the weakest swimmer on the team when she first joined but improved significantly through disciplined training. Kayadelen has lived in Germany, Türkiye, South Africa, the United Kingdom, and Switzerland, and continues her professional career in Zurich.

Kayadelen began her open water swimming career in 2008 by participating in the Istanbul Strait Swim. That same year, during a 10-kilometer national championship race in the Sea of Marmara—a race that offered selection for the national team—she lost consciousness and awoke in the emergency room. This incident triggered a long-standing fear of cold water. During her second participation in the Istanbul Strait Swim, she won first place in the overall classification and realized she was more successful in open water than in pool swimming. She subsequently competed in the Çanakkale Strait Swim and the Kaş-Meis swimming marathon, winning first place overall in both events. She represented Türkiye at the European Open Water Swimming Championships and then participated in the Ocean Man race, where she finished first overall in the 10-kilometer category, earning qualification for the World Championships. Prior to the pandemic, she represented Türkiye at an event held in Cancún, Mexico.

To overcome her fear of cold water, she began gradual cold water training. During this process, she became the first Turkish woman to cross the English Channel as part of a team, and later the first Turkish woman to cross the North Channel between Ireland and Scotland as part of a team. Water temperatures during the North Channel crossing were recorded at 14–15 degrees Celsius. In March 2020, she swam the approximately 11-kilometer route between Robben Island—where Nelson Mandela was imprisoned—and Cape Town, South Africa, in water at 14 degrees Celsius and among great white sharks; this achievement made her the first Turkish woman to complete this route. For safety, a magnetic field device was used on the support boat, and magnets were attached to her body. During the pandemic, she remained in South Africa for a period and wrote her book during this time.

^{Deniz Kayadelen, Ice Swimming Championship (AA)}

Kayadelen became the first Turkish woman to compete in the World Ice Swimming Championships organized by the International Ice Swimming Association (IISA). At the 4th World Championship in 2022, she won gold in the 500-meter freestyle in the 35–39 age group with a time of 8 minutes and 1 second, and earned a total of three gold and two silver medals at the event. In January 2023, she competed again at the championship held in Samoëns, France. At the 2023 championship, she became world champion in the 100-meter butterfly in the 35–39 age group. She won a total of five gold and four silver medals in the 100-meter and 50-meter butterfly events. At the 6th IISA Ice World Championship in 2025, she reclaimed her world champion title by finishing first in the 500-meter freestyle and placed third in the 250-meter and 100-meter freestyle events. Throughout her career, she has won a total of six world championships and two European championships. She has also represented Türkiye internationally in the 500, 200, 100, and 50-meter freestyle and butterfly events, and currently holds the national records in Türkiye for the 200-meter butterfly and 1500-meter freestyle in her age category.

Deniz Kayadelen entered the Guinness Book of World Records after swimming for five minutes in 3-degree Celsius water at a glacial lake located at 6,400 meters above sea level on Putha Hinchuli mountain in Nepal. This endeavor was part of a project organized by a South African team to raise awareness about global warming and to raise donations for children in Africa and Nepal. During preparation, she spent 15 days camping at the mountain, exposed to temperatures as low as minus 15 degrees Celsius. Having no prior mountaineering experience, she underwent a one-month preparation period before the attempt.

On July 20–21, 2023, Kayadelen swam solo across the English Channel between England and France. Her swim began at Samphire Hoe, a shoreline near Dover, England, and continued uninterrupted in sea water at approximately 16 degrees Celsius, concluding after 15 hours and 8 minutes at Strouanne Beach in France. With this 57-kilometer crossing, she became the fifth Turkish woman and the 17th Turkish swimmer overall to complete the English Channel. She was accompanied by her coach Kamil Reşa Alsaran and swimmer Emre Deliveli, both of whom had previously completed the same route. She reported experiencing numbness in her hands and feet during the third hour, energy loss during the fourth hour, and considered abandoning the crossing during the tenth hour. Her coach noted that her preparation lasted three years and included multiple cold water camps.

The Triple Crown, one of the most prestigious achievements in open water swimming, is earned by completing the English Channel, the Catalina Channel, and the 48-kilometer course around Manhattan Island in the Hudson River. After completing the English Channel, Kayadelen crossed the Catalina Channel during nighttime hours; the swim began at 9:00 p.m. and continued for eight hours in darkness illuminated only by moonlight. On August 21, 2024, she completed the final leg of the Triple Crown—the 48-kilometer Hudson River course around Manhattan—in 7 hours and 58 minutes, breaking the Turkish women’s record and becoming the fastest Turkish female swimmer to complete the Triple Crown. With this achievement, she became the first woman from Switzerland and the second German woman worldwide to earn the Triple Crown title. To date, fewer than 500 people worldwide have earned the Triple Crown.

^{Deniz Kayadelen, North Pole Swim (AA)}

On July 18, 2026, Kayadelen became the first Turkish athlete to swim at the North Pole, completing a 1,200-meter swim in 4-degree Celsius Arctic waters near the Svalbard archipelago. She undertook this journey with her 10-year-old daughter Alya; due to harsh weather conditions, she left her daughter at the hotel and did not bring her to the water’s edge. She has stated that this endeavor was planned as a preparatory step toward her goal of swimming in Antarctica. She associates this achievement at age 38 with the sense of responsibility she carries as a mother. Her future goals include swimming in Antarctica and completing the “Ocean Seven,” a seven-stage open water swimming series.

Deniz Kayadelen is an industrial/organizational psychologist trained in economic psychology. For over fifteen years, she served as a senior executive and consultant at Ernst & Young (EY), one of the world’s leading consulting firms, where she managed the talent development department in Switzerland. She provides consulting services to major corporations on talent management, change management, employee motivation, future professions, and competencies. She is a certified talent manager, certified change manager, and an ICF-accredited executive coach. She developed the “Peak Flow Methodology,” an integrative framework combining mindfulness, breathwork, neuroscience, and behavioral science. This methodology aims to translate the experiences she gained in extreme sports into strategic frameworks applicable to the business world.

Kayadelen is the author of the book “Out of Comfort Zone” (Turkish title: “Limitlerin Ötesinde”), which blends her personal life story with psychology. The book was originally written in English and later translated into Turkish, published in Türkiye starting in 2022 by Ceres Yayınları. The English edition appeared on Amazon’s bestseller list. The book covers topics such as overcoming fear, meditation, breathing exercises, and nutrition, alongside her experiences in sports and business, including world championships, losses, and divorce. She is currently working on a new book titled “From Fear to Peak Flow.”

As an international speaker, she has been nominated by Forbes and has spoken twice on the TEDx stage. She regularly speaks at high-level events for Fortune 500 companies. Her talks address themes such as pushing beyond limits, overcoming fear, change management, employee motivation, talent development, and future professions. In her speaking and consulting work, she integrates her corporate consulting experience, extreme sports psychology, and positive psychology-based coaching methods.

^{Alya (AA), daughter of Deniz Kayadelen}

Among the awards and honors received by Deniz Kayadelen are the “Most Inspiring Leader” award presented by Microsoft MSN in 2025 and the “Most Influential Woman” award presented by the NY Journal in 2023. She has also been recognized as one of the top 100 speakers globally. She speaks English, German, and Turkish.

Deniz Kayadelen holds dual citizenship in Türkiye and Germany. She resides in Männedorf, Switzerland, on the shores of Lake Zurich. She has one daughter named Alya.