Sienna Yeo is a talented and dynamic lock forward for the Newcastle Knights, quickly emerging as one of the most promising young middles in the NRLW. A proud junior of the Wollongong Collegians and a product of the Illawarra Steelers pathways, Yeo rose to prominence through her standout performances in the region's elite development system. She played an important role in the Steelers' Harvey Norman NSW Women’s Premiership Grand Final victory, contributing strongly off the bench as the side secured the title.

In 2024, Yeo further impressed as part of the extended NSW Under‑19s Origin squad, showcasing her growing reputation as a smart, hard‑working forward with natural ball‑playing ability. Her versatility and football intelligence made her one of the most highly regarded young forwards coming through the state system.

Ahead of the 2025 NRLW season, Yeo signed with the Newcastle Knights and made her debut in Round 1, immediately staking her claim as a reliable contributor in the middle. Across her rookie campaign, she played all 13 matches, delivering consistent defensive work, strong carries, and calm decision‑making. Her season included 263 tackles at a 91% efficiency rate, nearly 1,000 running metres, and two well‑earned tries, an outstanding return for a first‑year forward.

Her impact was immediate within the club environment, earning praise from Knights head coach Ben Jeffries, who highlighted her potential and seamless transition into the NRLW. The Knights moved quickly to secure her long‑term future, re‑signing Yeo until the end of 2027, reinforcing her status as a core piece of their forward pack for years to come.