Fireteam Sydney is a team of SPARTAN-IV supersoldiers of the Office of Naval Intelligence. Sydney, consisting presumably of five members, was assigned to the UNSC Infinity at some point before February of 2558. On February 18, 2558, Fireteam Sydney participated in the Infinity Saturday Night Cage Fight in a no-holds barred martial arts cage match. It is likely that they saw action on Requiem, although they have not been mentioned or seen.
- Fireteam Sydney was apparently proficient in martial arts, according to the Halo 4 Limited Edition.
- Halo 4 Limited Edition (Mentioned only)