 Peter FinchUmberto Nobile | Umberto Nobile |
 Sean ConneryRoald Amundsen | Roald Amundsen |
 Claudia CardinaleValeria | Valeria |
 Hardy KrügerEinar Lundborg | Einar Lundborg |
 Eduard MartsevichFinn Malmgren | Finn Malmgren |
 Grigoriy GayRudolf Samoylovich | Rudolf Samoylovich |
 Nikita MikhalkovBoris Chukhnovskiy | Boris Chukhnovskiy |
 Luigi VannucchiCaptain Zappi | Captain Zappi |
 Mario AdorfGiuseppe Biagi | Giuseppe Biagi |
 Donatas BanionisAdalberto Mariano | Adalberto Mariano |
 Massimo GirottiGiuseppe Romagna Manoja | Giuseppe Romagna Manoja |
 Yuriy SolominFelice Trojani | Felice Trojani |
 Otar KoberidzeNatale Cecioni | Natale Cecioni |
 Boris KhmelnitskyAlfredo Viglieri | Alfredo Viglieri |
 Yuri VizborFrantisek Behounek | Frantisek Behounek |
 Nikolay IvanovKolka Shmidt | Kolka Shmidt |
 Vladimir SmirnovShelagin | Shelagin |
 Tengiz ArchvadzeRenato Alessandrini (uncredited) | Renato Alessandrini (uncredited) |
 Rein ArenKarl Jõgi (uncredited) | Karl Jõgi (uncredited) |
 Heinz BraunReporter (uncredited) | Reporter (uncredited) |
 Anatoliy BystrovRinborg's Neighbor in the Hospital Room (uncredited) | Rinborg's Neighbor in the Hospital Room (uncredited) |
 Robert DaglishThe Reporter (uncredited) | The Reporter (uncredited) |
| FFeliksas EinasAmundsen's Servant (uncredited) | Amundsen's Servant (uncredited) |
| RRoland EngmannDuty Officer (uncredited) | Duty Officer (uncredited) |
 Boris GoldayevKolka Shmidt's Fellow Villager (uncredited) | Kolka Shmidt's Fellow Villager (uncredited) |
 Leonid KanevskyItalian Radio Operator (uncredited) | Italian Radio Operator (uncredited) |
 Viktor KharitonovPart-bit (uncredited) | Part-bit (uncredited) |
 Stanislav KhitrovRadio Operator of Icebreaker 'Krasin' (uncredited) | Radio Operator of Icebreaker 'Krasin' (uncredited) |
 Irakli KhizanishviliPomella (uncredited) | Pomella (uncredited) |
 Eve KiviThe Blonde Lady (uncredited) | The Blonde Lady (uncredited) |
