Jared Harris
Valery Legasov (5 eps)
Stellan Skarsgård
Boris Shcherbina (5 eps)
Emily Watson
Ulana Khomyuk (5 eps)
Paul Ritter
Anatoly Dyatlov (5 eps)
Jessie Buckley
Lyudmilla Ignatenko (5 eps)
Adam Nagaitis
Vasily Ignatenko (5 eps)
Sam Troughton
Alexandr Akimov (5 eps)
Robert Emms
Leonid Toptunov (5 eps)
Con O'Neill
Viktor Bryukhanov (5 eps)
Adrian Rawlins
Nikolai Fomin (5 eps)
Alan Williams
KGB Chairman Charkov (5 eps)
David Dencik
Mikhail Gorbachev (5 eps)
Mark Lewis Jones
General Pikalov (5 eps)
Ralph Ineson
General Tarakanov (5 eps)
Barry Keoghan
Pavel (5 eps)
Alex Ferns
Glukhov (5 eps)
Fares Fares
Bacho (5 eps)
Michael McElhatton
Prosecutor Andrei Stepashin (5 eps)
Michael Socha
Mikhail (3 eps)
Karl Davies
Viktor Proskuryakov (3 eps)
Jan Ricica
Oksana's Kid (3 eps)
Ron Cook
Old Maternity Doctor (2 eps)
Donald Sumpter
Zharkov (2 eps)
Philip Barantini
Bezpalov (2 eps)
Oscar Dyekjær Giese
Baranov (2 eps)
Baltasar Breki Samper
Ananenko (2 eps)
Gerard Kearns
Pravik (2 eps)
Povilas Jatkevičius
Kibenok (2 eps)
Darius Petkevičius
Local Husband (2 eps)
Amanda Drew
Kremlin Aide Female (2 eps)
Jamie Sives
Sitnikov (2 eps)
Douggie McMeekin
Yuvchenko (2 eps)
Cait Davis
Local Wife at Bar (2 eps)
Michael Shaeffer
Blond Man (2 eps)
Adam Lundgren
Brazhnik (2 eps)
Billy Postlethwaite
Boris Stolyarchuk (2 eps)
Jay Simpson
Perevozchenko (2 eps)
Ross Armstrong
Nikolai Gorbachenko (2 eps)
Paulius Markevičius
Aleksandr Kudryavstev (2 eps)
Joshua Leese
Kirschenbaum (2 eps)
Karolis Kasperavičius
Viktor Degtaryenko (2 eps)
Sam Strike
Misha (1 eps)
Sammy Hayman
Titenok (1 eps)
Matas Dirgincius
Vladimir Tishchura (1 eps)
Caolan Byrne
Day Shift Worker (1 eps)
Stephen Bisland
Night Shift Worker (1 eps)
Alex Blake
Petrovich (1 eps)
Matthew Needham
Dmitri (1 eps)
Rosie Sheehy
Nurse Pripyat (1 eps)
Tomas Žaibus
Soldier (Hospital) (1 eps)
Peter Guinness
Major Burov (1 eps)
Laurence Spellman
Commission Heli Pilot (1 eps)
Alison Pargeter
BCP HQ Aide Female (1 eps)
Victor McGuire
Garanin (1 eps)
Sakalas Uždavinys
Ilya Ivanovich Chulkov (1 eps)
Aidas Jurgaitis
Soldier (Shelter) (1 eps)
Aiste S. Gram
Bartender in Polyissa Hotel (1 eps)
Daniel Crossley
Stasiuk (1 eps)
Lucy Russell
Marina Gruzinskaya (1 eps)
Diarmaid Murtagh
Zukauskas (1 eps)
Natasha Radski
Russian News Reader (1 eps)
Yitzchak Averbuch
General (1 eps)
Joe Tucker
Plant Employee (1 eps)
Caoilfhionn Dunne
Yenina (1 eps)
Pandora Colin
Dr. Vetrova (1 eps)
Rachel Atkins
Niyazova (1 eps)
James Cosmo
Miner (1 eps)
Arnas Danusas
Soldier (Miner's Bus) (1 eps)
Michael Colgan
Mikhail Shadov (1 eps)
James Kermack
Miner (1 eps)
Karolis Vilkas
Miner (1 eps)
June Watson
Old Woman Babushka (1 eps)
Josef Altin
Soldier (1 eps)
Sergejus Ivanovas
Survey Soldier (1 eps)
Alexej Manvelov
Garo (1 eps)
Josef Davies
Janek (1 eps)
Velta Žygurė
Elderly Librarian (1 eps)
Paulius Cizinauskas
KGB Agent Library (1 eps)
Mark Bagnall
Jughashvili (Robot Operator) (1 eps)
Ian Pirie
Site Officer Masha (1 eps)
Andrew Sheridan
Biorobot (1 eps)
Lukas Malinauskas
Biorobot Soldier (1 eps)
Marius Karolis Gotbergas
Biorobot Soldier (1 eps)
Simonas Dovidauskas
KGB Driver (1 eps)
Hilton McRae
Judge Milan Kadnikov (1 eps)
Kieran O'Brien
Khodemchuck (1 eps)
Šarūnas Datenis
Soldier (Reactor Site) (1 eps)
Deividas Breivė
Soldier (Mobile Office) (1 eps)