|Cost||200 100 40 3|
|Defense||160 1 (+1)|
|Speed Multiplier on Creep||1.3|
|Speed on Creep||2.925|
The Swarm Host is a Zerg siege unit that requires an Infestation Pit. It attacks in the form of waves of two Locusts that spawn once the Swarm Host is burrowed on a timer. The Locusts are slow moving ground-to-ground units with a timed life that nonetheless extend the range of the Swarm Host beyond that of any other unit, especially with the Enduring Locust upgrade.
The primary function of the Swarm Host is to siege entrenched enemy positions such as expansions and gradually wear them down with wave after wave of reinforcements. Opposing armies that cannot kill or dislodge the burrowed Swarm Hosts may be forced into an unwinnable war of attrition.
Spawn Locusts: Births 2 Locusts which deal damage instead of the Swarm Host. Locusts last 15 seconds and can be attack rallied, there is however a 25 second cooldown on the use of this ability. It takes 5 seconds to cooldown after burrowing. This is an autocast ability, and therefore can be turned off.
Spawn Locusts is allowed in both forms of the Swarm Host, but shows a requirement to be burrowed. It is possible that this is to prevent abuse of burrow and unburrow resetting the timer. It may also be possible to use this as an advantage to "leap-frog" and confuse the enemy as to where the Swarm Host truly is.
 Competitive Use
A group of Swarm Hosts are strong against almost any mix of ground units as long as the Locusts are in range to attack the enemy. As such, keeping out of the Locusts' range are vital when fighting Swarm Hosts. Even if you get the chance to attack the Swarm Hosts themselves, the high DPS of the Locusts will often allow them to destroy your army before you have killed all Swarm Hosts (provided that you and your opponent have equal army size, upgrades and that the locusts are not blocked off).
To keep out of the Locusts' range, consider attacking with long range units (like Siege Tanks) or using air units. Alternatively, use area-damage units like High Templars or Banelings to quickly kill the locusts before they get in range and before the Swarm Hosts can spawn new ones.
When fighting with Swarm Hosts, consider helping the Locusts reaching their targets using Creep to speed them up, Fungal Growth to prevent the enemy from escaping, or Abduct to pull important foes into the range of the Locusts.
 Vs. Protoss
Since Protoss tend to build their armies up slowly, Swarm Hosts can easily be used to pressure a Protoss opponent before they have a chance to amass a "deathball". Particularly in the mid-game Protoss players will struggle against locusts as they cannot engage them effectively without Colossus or Carrier support.
 Vs. Terran
Can be used to try and break Terran Siege Tank lines or bunkers. Zerg players should be careful to not let their swarm hosts wander too close to the Terran army, since bio armies or Siege Tanks can take them down very quickly.
 Vs. Zerg
Not often used in this matchup due to their immobility and inability to counter the popular Mutalisk tech. Additionally, the slow speed of locusts compared to Zerglings make it difficult to defend counter-attacks. Can be used to break spinecrawler lines. Large numbers of Queens and Spore Crawlers are necessary to keep the Swarm Hosts safe from Mutalisks, which makes it difficult to attack or secure additional bases.
 Patch Changes
|Balance Update #1|
|Balance Update #2|
|Balance Update #4|
|Balance Update #8 |