Carriers are the capital ships in the Protoss air force, built at the Stargate with the Fleet Beacon as a prerequisite. Unlike other units, Carriers do not engage the enemy directly. Instead, they launch tiny Interceptors that attack in a swarm around the Carrier. The Carrier is a production facility as well; Carriers are responsible for training additional Interceptors. The Carrier initially warps in with four Interceptors available, and from there it can be ordered to train additional Interceptors (an ability that can be set to autocast) for 25 minerals each. The maximum number of Interceptors that any Carrier can hold at one time is eight. The speed with which the Carrier launches Interceptors can be improved by researching the Graviton Catapult upgrade at the Fleet Beacon.
When attacking, Carriers launch their available Interceptors towards the target, at a delay of 0.5 seconds per Interceptor; a full complement of Interceptors thus takes 4 seconds to all launch from the Carrier. The launch duration can be improved with the Graviton Catapult upgrade; this reduces the launch delay for Interceptors to 0.125s for the first four interceptors and 0.25s for the last four, thus more than halving the launch of a full complement of Interceptors to 1.5 seconds.
The Carrier's launch range is 8, meaning that an enemy target must be within range 8 before the Carrier will launch Interceptors at it. But after launching Interceptors, the Carrier can move back to a leash range of 14 before the Interceptors disengage and return to the Carrier. Interceptors will also return to the Carrier once the current target has been destroyed if the Carrier is not within launch range of any enemy targets. If the Carrier is attacking a target, moves out of launch range, and there is a closer target with the same priority in launch range, the Interceptors will switch their target to the closer one.
Note that manually assigning a target will cause the Carrier to move towards the new target if it is outside of launch range. However, if Interceptors have already been launched and are not already disengaging, it is possible to change targets and then take advantage of the leash range by immediately moving the Carrier back; the launched Interceptors will migrate to the new target without returning to the Carrier despite it being out of launch range, though they will switch targets as noted above if they perceive a closer threat in launch range unless they are continuously manually assigned the farther target. Any unlaunched or newly created Interceptors will not launch at a target outside of launch range, though, so Interceptor losses suffered will not be able to be replaced at leash range.
A Carrier's effective attack power is the attack of one Interceptor times the number of active Interceptors the Carrier has launched. Each Air Weapons upgrade level researched affects each Interceptor individually, so Carriers gain a large increase in effective attack power for each upgrade. Similarly, each point of armor on the target results in a large decrease in effective damage dealt, as the damage is reduced for each Interceptor's attack.
Current use in competitive play
Currently, Carriers are not widely seen in SC2 due to the inability of any build to safely transition to them. Though Carriers do not yet have a solid position in SC2 competitive play, they are extremely powerful versus stationary defenses and AI controlled units, since the AI will target the individual Interceptors first, not the Carriers themselves.
Generally speaking Carriers are not very good in Protoss vs. Protoss because they are easily countered by Stalkers + Sentries. Carriers can be used to counter Void Ray heavy builds together with Phoenixes since player with Void Rays will usually try to focus down the Carriers, therefore allowing Phoenixes to score free hits and decimate Void Ray army. Carriers should use hit and run tactics against them.
Once the late-game hits, Carriers and Void Rays can be an extremely powerful unit composition since Stalkers will get decimated by Void Ray's bonus damage to armored units once Carriers and Void Rays hit a critical mass. However one should be aware of Tempest + Void Ray composition since Tempests can snipe Carriers before they can do any harm. Also Tempests have lower supply cost than Carriers.
Vikings, while killed in 2 volleys by Carriers, are less than a third of the cost, and while one Carrier will defeat 3 Vikings, this is the only match-up where the Carrier wins cost-for-cost: 4 Vikings will defeat one Carrier, and 6 Vikings will defeat 2 Carriers if they focus their fire. Vikings are a very soft counter, though and can't kite Carriers after Interceptors grab a target, so with appropriate micro, Carriers can stay competitive. Marines can't out range a well placed Carrier (besides getting shredded by the Carrier's improved targeting AI), though if they can get within range, cost-for-cost, Marines are also a good defense. Terrans have the best options for killing Interceptors, so careful management of your squadrons is key.
Beware of heavy AA emplacements. A location fortified with Marines and Missile Turrets can quickly turn Interceptor squadrons into dust. Interceptors no longer recover max health between sorties as they did in Brood War, and while large numbers can withstand a serious beating overall, they will not last long enough to break a sustained anti air defense.
Be cautious of flying structures. Carriers will automatically launch Interceptor squadrons at targets in range, and clever Terrans may use this to tease your Interceptors into a hail of gunfire at minimal risk.
Battlecruisers are extremely dangerous to contend with. With 3 base armor, a Battlecruiser with equal upgrades takes 40% damage from Interceptors, and will wipe out a full squadron in half the time you need to take one down. Attempting to kill Battlecruisers with Interceptors can turn into a huge mineral drain that leaves your Carriers vulnerable. To top it off, a well placed Yamato Cannon can severely damage or kill your Carriers outright, making it a bad idea to go toe to toe against a Terran victory fleet.
Carriers are very powerful against a Terran that is going for a mechanical composition (which includes primarily Hellions, Siege Tanks, Thors, and Banshees). Carriers, if unscouted, supplement a typical Protoss composition very well because of the lack of anti-air in the Terran's army. However, it scouted, Vikings will almost definitely be made as a direct counter, so it is important to not over-commit to Carriers in this type of situation, and use them to either destroy the Terran army and/or to force an overproduction of Vikings.
Carriers can be used as an all-in in PvZ. Off of a Forge Fast Expand, if Carriers are made from hidden Stargates, the opponent can be caught significantly off-guard and immediately lose the game if not adequately prepared with anti-air.
Carriers with weapons and launch upgrade can be effective against Zerg if the Zerg player is not prepared to counter with Corruptors. Corruptors are a very strong unit against a Carrier, but they can be effectively kited due to a Carrier's superior range. Hydralisks can also be a problem as they are good at taking down Interceptors quickly. Hydralisks are not a large threat to Carriers, however, due to their slow movement speed and extremely low hit points.
The Carrier's role is primarily to force Corruptors from a Zerg and to add extra damage. Making several Carriers in late-game PvZ can cause the Zerg to overcompensate in Corruptors, because of the difficulty in knowing exactly how many Carriers the Protoss wants to make, and how many Corruptors to make per Carrier. Do note however that if a ground transition is made by the Protoss after the Carriers are killed the remaining Corruptors can be morphed into Brood Lords, which may pose a serious problem if you are not adequately prepared for them.
In conjunction with Archons and the Mothership, Carriers will decimate the Zerg's late-game Brood Lord/Infestor/Corruptor army composition. Carriers can easily pull back to the cover of the Archons while Corruptors try to focus fire on the Carriers and Mothership. Due to the AI, the Corruptors will stack up quite a bit when focusing the Carriers, thus rendering them susceptible for insane amounts of Archon splash damage. Once the Corruptors are dead, Brood Lords will fall along with the Infestors.
Carrier's quotes (video and sound) - YouTube video.
- Carrier rush was the object of Day Daily #188.
- The song Mr. Lonely (Sc2 Carrier Parody) laments that this unit is so unused in comparison to how much use it saw in Starcraft 1.