SINGAPORE - Naval diver Esther Tan almost did not make history as the crack unit's first-ever female in 2001.
She finished among the top of her naval officer cadet batch and aced her physical and medical tests, but she was not picked for the final - and most crucial - interview to qualify for the Naval Diving Unit.
The indignant 25-year-old challenged the decision. "I knew I had fulfilled all requirements so I just asked what else I lacked," she recalled.
That paid off and she landed an interview with the unit's then commander. Among other things, she could run 6km within 28 minutes and swim 50m in under a minute.
"All I thought was to convince him that I was confident that I could do it," she said.
She was accepted into the elite unit and went on to specialise in search-and-rescue operations and explosive ordnance disposal. She is now a major.
Despite blazing the trail as the first woman naval diver, the avid triathlete, who has taken part in more than 30 international marathons, triathlons, and Ironman and adventure races, still had to overcome her peers' pre-conceived notions.