UNSC Special Forces
SPARTANs are the most skilled and disciplined soldiers available to the UNSC. Conscripts to the second and third programs take part in intense training at an early age, and are given the performance enhancing MJOLNIR Powered Assault Armor and the Semi-Powered Infiltration Armor, generally to the SPARTAN-IIs and the SPARTAN-IIIs, respectively, (with the Special Warfare Command fireteam Noble Team being a known exception), making them extremely skilled in combat.
Below are all known SPARTAN squads and companies.
- SPARTAN Program
Many UNSCDF personnel were part of the ORION Project, specializing in covert operations, assassinations, and conducting high-priority, high-risk operations against enemy forces. Numerous units are under the supervision of Section Three within the Office of Naval Intelligence, which coordinates their special operations missions; one such unit would be the members of the various SPARTAN-II teams.
 Orbital Drop Shock Troopers
The Marines Corps' Orbital Drop Shock Troopers are an important part of any UNSC invasion force. Disciplined and skilled, they drop into the most hostile areas via SOEIVs. They attempt to complete some of the most difficult tasks in hostile areas, such as clearing enemy ground forces or establishing landing zones for incoming Pelicans.
Below are all known ODST units.
- 105th Marine Expeditionary Unit (SOC)
- 105th Drop Jet Platoon
- 340th ODST Combat Training Unit
- Echo Team
- Kilo Team
 Army Special Warfare Command
- Main article: Special Warfare Command
 List of appearances