What is the best way to counter a player who is using a lot of Carriers?
The main problem with carriers only really arrives if you allow your opponent to build a ton of them. Alone, like Carl Clover said, they're very weak.
The secondary problem with carriers is that they're often accompanied by a mothership, which complicates matters.
One of the best ideas to counter a protoss dead-set on going carriers is to scout and provide early pressure if you see him teching quickly to a fleet beacon. He's probably spending so much money on those buildings that he has a comparatively weak army, and you should be able to do a good deal of damage.
Often the answer to a question of "how do I counter X high tier unit?" isn't so much about countering that unit once it's built, but preventing it from coming out at all.
I'm a player who almost always goes for carriers in large games (3v3, 4v4, FFA).
As someone who uses a lot of carriers, I can tell you what I fear the most:
- Mass Vikings using focus fire. They are (way) faster than my carriers, and they have longer range. A decent number of Vikes can focus-kill a carrier in about 1 second.
- Defensively, if you support the Vikings with marines, it's even harder to deal with, since a large group of marines can very quickly kill all my Interceptors.
- Note that marines alone are terrible against carriers. You just can't catch them. Even if you kill my Interceptors, I just run away and rebuild them, or attack you somewhere else. If I've gotten to mass carriers, I probably have the resources to rebuild the Interceptors.
- Mass Stalkers with blink. If you don't have blink, forget it, I just run away and pick off the Stalkers that chase. Even with blink, I will try to run away over gaps, but obviously, that's harder than just running away over cliffs.
- Mass (more) Carriers with focus fire.
- Forget Mass Void Rays, UNLESS they are already charged up when the battle starts. Otherwise, by the time they are charged up, half of them will be dead, and game over. Your only chance here is to get into my base and be killing my dudes so that I'm forced to come and engage you while you are charged. Even then, I will come in focus-firing, so you better be ready to react with focus-fire instantly and not waste time killing Interceptors (I see that ALL the time).
- Infestors with Fungal Growth, Neural Parasite and Burrow, backed by mutas/hydras/corruptors
- Corruptors WITH corruption, backed by mutas or hydras.
- Corruptors alone aren't usually that effective against Carriers - I can focus fire too, and they're not too hard to run away from. Mutas alone are terrible against carriers, your bounce damage isn't very effective against the mass HP of a carrier. Mass hydras are terrible, I will always just run over a cliff or a gap and attack you somewhere else. However, if you can use fungal growth to freeze Carriers, or corruption to increase damage, and use mutas/hydras/corruptors to pick them off, then i'm in trouble.
Since nobody else has mentioned it yet...armor upgrades. The interceptor fires 2 attacks that do 5 damage each unupgraded. With a maximum of 8 interceptors per carrier, each +1 to armor reduces the total damage the carrier does by 16 per wave of interceptors. Most anti-air units will do fairly well if you spend an equal amount on them, especially if you can stay ahead in upgrades. Corrupter and vikings are especially effective.
Edit for example: Corrupters start with 2 armor, if your air armor upgrade is one ahead of the carriers' air attack upgrades then each wave of interceptors will do a mere 32 damage (80 - 16 * 3). If their attack is 1 ahead of your armor, your corrupters instead take 64 damage per wave.
If you are playing zerg, use corrupters, corrupt each carrier, and focus them down. If they have "a lot" of carriers, they spent a fortune creating them. If you spend a similar fortune on vikings or corrupters, you should come out OK.
For example, I just did a test using the Hard Counter map. 10 carriers got killed by 24 corrupters which cost me less minerals and gas. (and quite possibly build time, though that varies with a lot of things)
Vikings and corrupters both counter carriers. If anything carriers are under powered.
This depends on how many carriers. At 10 carriers there's no straight counter-that's 160 intercepters, the best answer you can get is to run them around, stop them from attacking, keep them on the defensive.
As a Zerg you will want to go mass Hydra, mass corruptor is useless against that much DPS, they fire too slowly. Infestors, especially with their ability to cast their spells burrowed, are fantastic. What I'd suggest doing is building a few vipers, abduct what you can without risking your entire army, never take a straight up fight until they're under ~5 carriers. This game will go long, and it will not be fun, your goal is to mine out as many bases as possible without being forced into an engagement-this might mean losing a few bases. Take what buildings of theirs that you can without backing yourself into a corner.
TL;DR, 4+ infesters so that you can fungle Intercepters, killing them with mass hydra, having a few banelings for the mostly-adept ground army they'll certainly have.
Typically, you only see mass carrier in team games, like 3v3. So long as you scout early on, it's very easy to beat with the right build.
If I'm protoss, I go straight for a robo and a dark shrine. Most players tech'ing into carriers will cannon the front of their base, and skip getting a robo. So their detection is weak. By the 6 min mark, I have a warp prism in the back of their base warping in DTs. That will usually set their team back enough that we end up overrunning them before they can get mass carriers out.
If I'm zerg, I focus on getting 3 saturated bases, 2 spires and then start cranking out upgraded corrupters. 3/3 corruptors in mass will murder a fleet of carriers. Just be sure to make them focus fire the carriers and not your units shoot at interceptors.
If I'm terran, I usually go for 3 bases and then mass vikings. Fully upgraded mass marine with stim is probably more optimal. I just tend to play better with mech.
I'd be curious if anyone has variants which might work better?