Tonkin came to national attention for portraying Cleo Sertori in H₂O: Just Add Water. Having relocated to Los Angeles in 2011, she went on to play Faye in The Secret Circle and rejoin her Just Add Water co-star Claire Holt (Rebekah) as Hayley in The Vampire Diaries, which led to them both reprising their roles as part of the main cast of its spinoff, The Originals.
- 2010 Tomorrow: When the War Began as Fiona Maxwell
- 2012 Bait 3D as Jaime
- 2014 The Ever After as Mabel
- 2016 Billionaire Ransom as Amy Tilton
- 2006 — 2010 H₂O: Just Add Water as Cleo Sertori
- 2009 — 2010 Packed To The Rafters as Lexi
- 2010 Home and Away as Adrian Hall
- 2011 — 2012 The Secret Circle as Faye Chamberlain
- 2012 — 2018 The Vampire Diaries Universe as Hayley Marshall
- 2015 Stalker as Nicole Clark
- 2017 Pillow Talk as Sonja
- 2018 Safe Harbour as Olivia Gallagher
- 2018 The Affair as Delphine
- 2019 Bloom as Young Gwen Reid
This actress provides examples of:
- Fake American: She's Australian, but some of her most famous characters, like Hayley and Faye, are American.
- Ms. Fanservice: She's not shy about showing off her toned body, and The Affair features her first nude scene.
- Playing Against Type: Her breakout role as Cleo is a Shrinking Violet, but Tonkin would later be cast as lots of Alpha Bitches and Action Girls.
- Star-Making Role: Cleo in H2O: Just Add Water.