After doctors advised her to give up land sports for injuries, she joined her school's water polo team.

Her first international appearance was as a 17-year-old at the 1983 FINA Women's Water Polo World Cup in Sainte-Foy, Quebec, Canada, where the Australian team finished in third place.

[1] With the national squad Watson won gold medal at the 1984 FINA Women's Water Polo World Cup in Irvine, California, United States.

At 20 years old, Watson was part of the team that won gold at the 1986 World Aquatics Championships in Madrid, Spain.

By defeating the United States 4-3 in the final, home team Australia won the first gold medal in women's water polo at the Sydney Summer Olympics,[3][4] making Watson the first female athlete to win gold in water polo both at the Olympics and at the World Championship.