Armed with only one word - Tenet - and fighting for the survival of the entire world, the Protagonist journeys through a twilight world of international espionage on a mission that will unfold in something beyond real time.
| Protagonist | John David Washington |
| Neil | Robert Pattinson |
| Kat | Elizabeth Debicki |
| Sator | Kenneth Branagh |
| Priya | Dimple Kapadia |
| Crosby | Michael Caine |
| Fay | Martin Donovan |
| Wheeler | Fiona Dourif |
| Volkov | Yuri Kolokolnikov |
| Mahir | Himesh Patel |
| Barbara | Clémence Poésy |
| Ives | Aaron Taylor-Johnson |
| Max | Laurie Shepherd |
| Rohan | Anthony Molinari |
| Passenger | Juhan Ulfsak |
| Well-dressed Man | Jefferson Hall |
| Uniformed Official | Ivo Uukkivi |
| Driver | Andrew Howard |
| SWAT / Target | Rich Ceraulo Ko |
| SWAT 2 | Jonathan Camp |
| SWAT 3 | Wes Chatham |
| Ukrainian SWAT | Sander Rebane |
| Male Voice (voice) | Josh Stewart |
| Sanjay | Denzil Smith |
| Steward | Jeremy Theobald |
| Shipley's Representive | Tom Nolan |
| Gaunt Russian | Marcel Sabat |
| Nanny | Julia-Maria Arnolds |
| Klaus | Jack Cutmore-Scott |
| Young Sator | Adam Cropper |
| Gold Bar Thief | Tony Christian |
| Blue Co-Pilot | Jan Uuspõld |
| Police Operator | Kaspar Velberg |
| Police Supervisor | Sergo Vares |
| Policeman Passenger | Rain Tolk |
| Medic | Henrik Kalmet |
| Red Soldier 1 | Sean Avery |
| Red Soldier 2 | John Douglas |
| Junior Crew Member | Seb Carrington |
| Blue Team Soldier | Matthew Marsden |
| Toby (uncredited) | Mark Krenik |
| Tourist in Oslo (uncredited) | Kenneth Wolf Andersen Haugen |
| Usher (uncredited) | Marek Angelštok |
| SWAT (uncredited) | Klaus Peeter Rüütli |
| SWAT (uncredited) | Daniel Olesk |
| Usher (uncredited) | Ingrid Margus |
| Tourist in Oslo (uncredited) | Carina Velva |
| Russian Soldier (uncredited) | Glenn Lawrence |
| Flight Attendant Anne (uncredited) | Katie McCabe |
| Art Gallery Employee (uncredited) | Ronald Pelin |
| High Security Guard (uncredited) | Schezaad Ausman |
| Military Officer (uncredited) | Anterro Ahonen |
| Pedestrian (uncredited) | Aleksei Podlesnov |
| Soldier (uncredited) | Trent Buxton |
| Soldier (uncredited) | Jess Weber |
| Soldier (uncredited) | Martin Tõnumaa |
| Soldier (uncredited) | Lisa Marie |
| Coat Check Girl (uncredited) | Loora-Eliise Kaarelson |
| Audience Member (uncredited) | Andres Oja |
| Audience Member (uncredited) | Anton Klink |
| Hostage (uncredited) | Viktoria Jelizarova |
