 Walter PidgeonAdmiral Harriman Nelson | Admiral Harriman Nelson |
 Robert SterlingCaptain Lee Crane | Captain Lee Crane |
 Barbara EdenLieutenant Cathy Conners | Lieutenant Cathy Conners |
 Peter LorreComm. Lucius Emery | Comm. Lucius Emery |
 Joan FontaineDr. Susan Hiller | Dr. Susan Hiller |
 Michael AnsaraDr. Miguel Alvares | Dr. Miguel Alvares |
 Frankie AvalonLieutenant Chip Romano | Lieutenant Chip Romano |
 Regis ToomeyDr. Jamieson | Dr. Jamieson |
 John LitelVice Admiral B.J. Crawford | Vice Admiral B.J. Crawford |
 Howard McNearCongressman Llewellyn Parker | Congressman Llewellyn Parker |
 Henry DaniellDr. Zucco | Dr. Zucco |
 Robert EastonSparks | Sparks |
 Charles TannenCPO Mack Gleason | CPO Mack Gleason |
 Mark SladeSeaman Jimmy 'Red' Smith | Seaman Jimmy 'Red' Smith |
 Del MonroeSeaman Kowski | Seaman Kowski |
 Jonathan GilmoreSeaman George Young | Seaman George Young |
| AAnthony MonacoCookie | Cookie |
 Skip WardCrew Member | Crew Member |
| MMichael FordCrew Member | Crew Member |
| WWilliam HerrinCrew Member (Uncredited) | Crew Member (Uncredited) |
 Robert BuckinghamCrew Member (Uncredited) | Crew Member (Uncredited) |
| RRichard AdamsCrew Member (Uncredited) | Crew Member (Uncredited) |
 Jimmy MurphyCrew Member (Uncredited) | Crew Member (Uncredited) |
| GGeorge DiestelLieutenant Hodges (Uncredited) | Lieutenant Hodges (Uncredited) |
| LLarry GrayDr. Newmar (Uncredited) | Dr. Newmar (Uncredited) |
 David McLeanNed Thompson (Uncredited) | Ned Thompson (Uncredited) |
| EEdward RickardOfficer (Uncredited) | Officer (Uncredited) |
 Charles DierkopSeaview Pilot (Uncredited) | Seaview Pilot (Uncredited) |
 Kendrick HuxhamUN Committee Chairman (Uncredited) | UN Committee Chairman (Uncredited) |
 Art BakerUN Commentator (Uncredited) | UN Commentator (Uncredited) |
