Main •
Ioan Gruffudd as Dr. Daniel Harrow, senior forensic pathologist at the fictitious Queensland Institute of Forensic Medicine (QIFM), an intelligent and unconventional scientist who delves for the real reasons people have died, though he hides his own dark secrets. •
Anna Lise Phillips as Stephanie Tolson, Daniel's ex-wife, Fern's mother, and a primary school teacher (seasons 1–2). •
Miriama Smith as Renae Warrington, Maxine's replacement as QIFM director, hired to implement quotas and cost-cutting restructure, shares custody of son, Louie (season 3). •
Harrison Gilbertson as James Reed, Tanya's son, he claims to be Daniel's long-estranged English-born son (season 3). •
Uli Latukefu as Jesse Walsh, Stephanie's boyfriend (season 1). •
Diana Glenn as Mila Zoric, businesswoman, mother of Max (season 3). •
Tim Ross as Dr. Ben Patterson, paediatric surgeon, Grace's estranged, then divorced husband (season 3). • Hugh Parker as Doug Hinton, Queensland Deputy Coroner (seasons 2–3). •
Tasneem Roc as Jill McCloud, Queensland police drug squad detective (seasons 1–2). •
Ditch Davey as Robert Quinn, former police sergeant, Stephanie's second husband, Fern's stepfather, missing for 10 months (season 1). •
Sara Wiseman as Tanya Ann Hain (previously Tanya Ann Reed), English woman, Daniel's long-ago girlfriend, mother of James (season 3). •
Geoff Morrell as Dr. Laurie Badcoe, North Queensland forensic pathologist, previously Daniel's supervisor (season 2). • Andrew Buchanan as Kiriakos, Queensland police Inspector (season 1). • Josephine Flynn as "Detective": plain clothes Queensland police detective (season 2). •
Heather Mitchell as Louise Whitehall (previously Louise Chester), widow of Dr. Maurice Chester, Francis' mother (season 2). • Anthony Standish as Tim Markides, chemist, employed Fern, gambler (season 2). • Erroll Shand as Brendan Skene, ex-prisoner, gambler, illiterate, confesses to shooting Daniel (season 2). • Ed Wightman as Yellowly,
SOCO allied with police and QIFM (season 1). • Sophia Emberson-Bain as Sage Wu, Ben's divorce lawyer, becomes his fiancée (season 3). • Virginie Laverdure as Bec Crowley, Queensland police superintendent, Bryan's boss (seasons 2–3). • Dorian Nkono as Lewison, underworld contact, known to Fern (season 1). • Oliver De Los Santos as Louie Warrington, Renae's young son, hangs around QIFM (season 3). • Steven Lunavich as Dieter Schuh, pawnbroker, used by Fern and Daniel (season 1). • Korey Williams as "Drug squad officer" (season 2) and "Henchman #2" (season 3). •
Gary Sweet as Bruce Reimers, Olivia's father, suspects her fiancé of killing Olivia (season 1). •
Ian Bliss as Charlie Oberg •
Kaiya Jones as Madison Moreland •
Joe Klocek as Sean Paulson •
John Batchelor as Clayton Pike •
Laura Gordon as Audrey •
Marta Kaczmarek as Ruth Kovacs •
Georgina Naidu as Alison Chen •
Mercia Deane-Johns as Sofia Calanna •
Scott Johnson as Reverend Joshua Mercado •
Richard Brancatisano as Sergeant Gabriel Capello •
Anthony Brandon Wong as Dave Young (season 3) •
Lasarus Ratuere as Myles Hendry ==Episodes==