- Ed Bishop
- Commander Ed Straker
- Michael Billington
- Colonel Paul Foster
- Gabrielle Drake
- Gay Ellis
- Wanda Ventham
- Col. Virginia Lake
- Derren Nesbitt
- Craig Collins
- Vladek Sheybal
- Dr. Doug Jackson
- Patrick Allen
- Turner
- Deborah Grant
- Linda Simmonds
- George Sewell
- Col. Alec Freeman
- Shane Rimmer
- Lt. Bill Johnson / Alien / CIA Agent (uncredited)
