- Eric Dane as Commander Tom Chandler, commanding officer of the USS Nathan James (DDG-151).
- Rhona Mitra as Dr. Rachel Scott, a paleomicrobiologist.
- Adam Baldwin as Commander Mike Slattery, executive officer of the USS Nathan James.
- Charles Parnell as Hugh Jeter, the ship's command master chief.
- Sam Spruell as Quincy Tophet, a paleomicrobiologist, and implied to be a Russian mole.
- Travis Van Winkle as Lieutenant Danny Green, leader of a SEAL team aboard the USS Nathan James.
- Marissa Neitling, as a Lieutenant Kara Foster, an officer working in the Combat Information Center.
- Christina Elmore as Lieutenant Alisha Granderson, co-helmsman of the USS Nathan James.