- Billy Treacy
- Â Agent Liam / ... 24 episodes, 2008-2023
- Sebastian Treacy
- Â Dan the Cyborg / ... 16 episodes, 2008-2010
- Jaime Carroll
- Â Agent Mortis / ... 16 episodes, 2008-2022
- Allan Rafferty
- Â Robin Turner / ... 13 episodes, 2010-2022
- Harry Williams
- Â Ben / ... 10 episodes, 2008-2009
- Matt Williams
- Â Danny / ... 10 episodes, 2008-2009
- Jon Gransden
- Â Captain Tobias / ... 8 episodes, 2009-2011
- Chris Walker-Thomson
- Â The Executive / ... 8 episodes, 2009-2012
- Eleanor Hawfield
- Â Hannah / ... 5 episodes, 2009-2010
- Daniel Sherratt
- Â Keith 'Nidge' Cookson / ... 4 episodes, 2011-2022
- Tim Lyth
- Â Clinton Frost / ... 4 episodes, 2011-2022
- Alex Matthews
- Â Colonel Radcliffe-Naismith 4 episodes, 2010-2012
- Jacob Kay
- Â Jackson Turner 4 episodes, 2011-2022
- Sam Woodhall
- Â Alec McDonald 4 episodes, 2011
- Andrew Epsley
- Â The Contact 4 episodes, 2011
- Charlie Holliday
- Â Jennifer Jones 3 episodes, 2019-2022
- Andy Fowler
- Â Gabriel Messinger 3 episodes, 2019-2022
- Ethan Williams
- Â Cyber-Kuio / ... 3 episodes, 2008
- Chris Johnson
- Â Stan the Hologram 3 episodes, 2019-2022
- Robert Lee
- Â Mr. Devine / ... 3 episodes, 2019-2022
- Jess Owen
- Â Amy 3 episodes, 2019-2022
- Stephen Prescott
- Â Mayor Charles Bishop 3 episodes, 2019-2022
- Michael .C. Angell
- Â Chief of Staff 3 episodes, 2019-2022
- Laura Daykin
- Â Katrina Mills / ... 3 episodes, 2008-2010
- James Ellison
- Â Cypher 2 episodes, 2019-2020
- Nathan Ewing
- Â Colonel Ryan / ... 2 episodes, 2019-2020
- Oliver Alexander
- Â Weasel 2 episodes, 2020-2022
- Donal Borg-Neal
- Â Knuckles 2 episodes, 2020-2022
- Liam Fish
- Â Mr. Shephard / ... 2 episodes, 2020-2022
- Matthew Perks
- Â Agent Obadiah 2 episodes, 2011
- Abbie Plant
- Â Scarlett Brooke 2 episodes, 2011-2012
- Luke Pond
- Â The Fairy 1 episode, 2010
- Sally Treacy
- Â Receptionist 1 episode, 2011
- Matt Beale
- Â News Reporter #1 1 episode, 2011
- Chris Treacy
- Â Gordon Davids 1 episode, 2010
- Tom Mullarky
- Â BioTech Guard #1 1 episode, 2011
- Grant Battersby
- Â Walter Reich 1 episode, 2022
- Adam Massingham
- Â BioTech Guard #2 1 episode, 2011
- John Hutch
- Â Zakatron Oracle 1 episode, 2010
- Lily Dong
- Â Agent Nikita 1 episode, 2019
- Christopher Palmer
- Â Richard 1 episode, 2022
- Chris Ryder
- Â Security Guard 1 episode, 2011
- Abigail Ramsdale
- Â Judy Bishop 1 episode, 2020
- Nancy Carroll-Egan
- Â Lizzie Bishop 1 episode, 2020
- Harry Hulme
- Â CERBERUS Soldier / ... 1 episode, 2022
- James Coaton
- Â DIA Agent 1 episode, 2019
- Ryan Clarke
- Â Scott 1 episode, 2020
- Tomas van der Merwe
- Â Police Officer 1 episode, 2022
- Rick Wiltshire
- Â CERBERUS Soldier / ... 1 episode, 2022
- David Few
- Â PC Fletcher 1 episode, 2019
- Aysha Carroll
- Â Bio-Tech Guest 1 episode, 2022
- Rebecca Hough
- Â Dispatch 1 episode, 2019
- Arron Carroll
- Â Bio-Tech Guest 1 episode, 2022
- Gary Carroll
- Â The Bounty Hunter 1 episode, 2019
- Rachael Warren
- Â Lizzie Bishop 1 episode, 2022
- Andy Flowers
- Â Mugging Victim 1 episode, 2022
- Sarah Gibbs
- Â Girl with Phone 1 episode, 2020
- Beckie Hough
- Â Train Station Passenger 1 episode, 2022
- Oliver Harrop
- Â Venator 1 episode, 2020
- Joe Shields
- Â Train Station Passenger 1 episode, 2022
- Andrea Carroll
- Â Newsreader 1 episode, 2022
- Shervin Alenabi
- Â Zak Trevers 1 episode, 2011
- Ross Cawton
- Â George Hunt 1 episode, 2011
- David Mooney
- Â Radio Speaker 1 episode, 2011
- Ciara Beighton
- Â Zoey 1 episode, 2011
- Dale Farrow
- Â Street Gang 1 episode, 2011
- Emma Crichton
- Â Katrina Mills 1 episode, 2011
- Nathan Mullins
- Â The Judge 1 episode, 2011
- Matt Gregory
- Â News Reporter #1 1 episode, 2011
- Simon Tasker
- Â Undercover Hoody 1 episode, 2011
- Jonathan Miles
- Â UNIT Scientist 1 episode, 2011
- Andy Rayner
- Â Street Gang 1 episode, 2011
- Andy Mansell
- Â Street Gang 1 episode, 2011
- David McLaughlin
- Â Shareholder 1 episode, 2011
- Laura Haruk
- Â Receptionist 1 episode, 2012
