In 2019, Chelsey debuted for New Zealand at the World Aquatics Championships held in Gwangju, South Korea, where she competed in the women's 50 metre freestyle, Chelsey and the women's 4 × 200 metre freestyle relay, where New Zealand finished in 10th place.

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Chelsey additionally represented New Zealand at the World Aquatics Championships in Budapest, Hungary where she swam both the 50m Freestyle and the mixed 4x100 Freestyle Relay where they finished 9th. 

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Chelsey is a highly dedicated athlete who is constantly striving to improve her performance. She spends countless hours training and is always looking for ways to enhance her skills and technique. Her commitment to the sport has earned her a reputation as a hard-working and determined individual, and she is highly respected by her peers and coaches alike.

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As Chelsey continues to train and compete, there is no doubt that she will achieve even greater success in the years to come. Her talent and drive have already earned her a place among the best swimmers in the world, and with her passion and dedication, she is poised to become one of the most accomplished athletes in New Zealand's swimming history.