Varied by mission
The size of Red Team was fluid, ranging from as few as six members to almost two dozen depending on the needs of a given mission. They actively participated in several battles, including the Battle of Arcadia, the Battle of Jericho VII, the Battle of Sigma Octanus IV, and the Fall of Reach.
 Early Human-Covenant War
In February 2531, Red Team was under the leadership of Jerome-092. It was a nine-person unit, with the core of the team comprised of Jerome, Douglas-042, and Alice-130, and the other six members organized into Team Omega; these Spartans' MJOLNIR Mark IV armor was equipped with a prototypical energy shield system which would not become standard until the release of the Mark V twenty years later. Red Team participated in the Battle of Arcadia, where they assisted forces from the UNSC Spirit of Fire to evacuate Arcadian civilians and to destroy a Covenant excavation operation at a complex of Forerunner ruins. After Covenant forces had been driven from Arcadia, Jerome, Douglas, and Alice remained with the ship's forces. After the Spirit of Fire's crew destroyed a Forerunner shield world in order to eliminate a fleet of Forerunner ships which the Covenant planned to reverse-engineer and use to swiftly eradicate humanity, the three Spartans were presumed missing in action with the rest of the ship's crew.
During the Battle of Sigma Octanus IV in July 2552, Red Team was led by Joshua-029. They were tasked with scouting the city of Côte d'Azur's wharves while Blue Team planted a HAVOK tactical nuclear weapon in the sewers beneath the city. In the meantime, they rescued numerous civilians, the only ones the Covenant had not massacred.
 Fall of Reach
- Main article: Fall of Reach
On August 23rd, 2552, Red Team was rumored to be deployed to defend civilian evacuation operations on Reach; however, as personnel assigned to Operation: RED FLAG were kept unaware of the invasion, these rumors were likely untrue. By August 30th, they had been assigned to the UNSC Pillar of Autumn to participate in Operation: RED FLAG. However, before the Autumn could exit the system and initiate the mission, all UNSC ships were recalled to defend Reach. Red Team, consisting of twenty-two members under the command of Fred-104, was deployed to the surface of Reach to defend the generators that powered the planet's twenty orbital defense platforms.
Though they inflicted heavy damage on the Covenant, including destroying a Covenant cruiser and a military base set up to secure the ground, many members of Red Team were killed during their insertion and in the engagements that followed.
 Known members
Although Red Team generally operated at a size of around six members, more Spartans could be selected for missions that called for a larger force.
- Kelly-087 - Second in command during the Fall of Reach. Rejoined Blue Team after the Fall of Reach.
- Jerome-092 - Commander during the Outer Colony campaigns until his disappearance in 2531.
- Frederic-104 - Commander until the Battle of Earth, taking command of Blue Team.
- Beta Red Actual - Leader of Team Beta during the Fall of Reach.
 Fall of Reach splinter arrangement
After their D77-TC Pelican, Bravo 001, was shot down during the Fall of Reach and four team members were killed, the surviving members of Red Team were split into four groups: Alpha, Beta, Gamma, and Delta.[note 1]
 Halo Wars gameplay
In Halo Wars, the members of Red Team have prototypical energy shields in addition to health. All three Spartans count as hero units; if their health is depleted, instead of dying, they are "downed", at which point their health bar begins to regenerate. Once the health bar is at least half full, the downed Spartan can be revived by touching them with any other unit under the player's of allies' control. The Spartans are capable of hijacking enemy vehicles and commandeering friendly vehicles, similar to the FPS games, but at a much slower rate. Because Spartans are more effective than standard soldiers with the same equipment, any vehicle driven by a Spartan receives a stat boost and the ability to earn more veterancy points. Spartans cannot be harmed by Flood infection forms while their shields are intact, and as hero units, they are immune to being infected.
Red Team competing with Black Team during a training exercise.
 List of appearances
- Halo: The Fall of Reach (First appearance)
- Halo: First Strike
- Halo: Ghosts of Onyx
- Halo Wars
- Halo: Reach (Mentioned only)
- Halo: Fall of Reach
- ^ Several sources, (see above), explicitly state that Red Team consisted of twenty-two members during the mission to secure the orbital defense generators. Four members, including Malcolm-059, were killed on impact after jumping from Bravo 001, which would leave eighteen survivors. According to Halo: First Strike, Alpha and Gamma teams each consisted of three members, Delta had six, and Beta had eleven, (the latter count being reiterated in Halo: Reach), paradoxically resulting in twenty-three survivors. However, the 2011 definitive edition of the novel states that Team Beta had six members, leaving eighteen survivors, which is consistent with twenty-two total Spartans, four of whom died upon impact.
- ^ Halo Wars, campaign levels Arcadia City and Arcadia Outskirts
- ^ a b Halo: The Essential Visual Guide, page 119: "Energy shielding was a key feature of Mark V, although other Spartan squads had field-tested prototypes of this technology as early as 2531."
- ^ Halo: Reach, campaign level New Alexandria
- ^ a b Data Drops
- ^ Halo Wars timeline
- ^ Halo: The Fall of Reach Definitive Edition
- ^ Halo: First Strike (2010 edition)
- ^ Halo Waypoint: Defiant to the End
- ^ Halo: Combat Evolved Anniversary Library - Pelican