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Shoots homing torp-e-darts at nearby Bloons. Must be placed in water.
~ Bloons TD 6 Description

Monkey Sub is a tower from Bloons TD 5 Mobile that was introduced on Friday, November 22, 2013 in the 2.3 Christmas update and on Bloons TD Battles on Friday, May 16th in the 1.8 update. It is unlocked from the Christmas gift (Popping 250,000 Bloons), along with the maps Ice Flow and Challenger Deep. This tower is a good starting tower on water maps since it is both cheap and powerful.

On Wednesday, July 22nd, 2015, The Monkey Sub has been released on the Flash version of Bloons TD 5 with a new appearance and different artwork.

Game appearances[]

Tower Costs[]

Game Easy Medium Hard Impoppable
Bloons TD 5 $295 $350 $380 -
Bloons TD 5 Mobile $295 $350 $380 $420
Bloons TD Battles $350
Bloons TD Battles Mobile $350
Bloons Monkey City $TBA
Bloons Monkey City Mobile $TBA
Bloons TD 6 $275 $325 $350 $390


Bloons TD 5[]

The Monkey Sub first made its debut in BTD5 Mobile. Eventually, it was made available in BMC Mobile, BTDB Mobile, and even BTD5 Flash. It can be upgraded as a support tower or as an attacking tower. Its signature special upgrade is the Advanced Intel, which allows the Monkey Sub to attack bloons within any tower's radius.

Path 1[]

Barbed Darts Icon BTD5.png
Barbed Darts
COST: $255 / $300 / $325 / $360
Description: Darts pop up to 3 bloons each.
Effect: Self-explanatory
Advanced Intel Icon BTD5.png
Advanced Intel
COST: $425 / $500 / $540 / $600
UNLOCK: 2,500 XP
Description: Allows long range targeting of bloons that are in the radius of your other towers and receives camo detection in the radius of any tower with camo detection.
Effect: Self-explanatory
Submerge and Support Icon BTD5.png
Submerge and Support
COST: $425 / $500 / $540 / $600
UNLOCK: 3,000 XP
Description: Activate submerge using target option to permanently reveal camo bloons in its radius.
Effect: Self-explanatory
Bloontonium Reactor Icon BTD5.png
Bloontonium Reactor
COST: $2,125 / $2,500 / $2,700 / $3,000
UNLOCK: 35,000 XP
Description: Activate submerge using target option to detect camo, pop bloons, and reduce water tower cooldowns by 15%.
Effect: Self-explanatory

Path 2[]

Twin Guns Icon BTD5.png
Twin Guns
COST: $385 / $450 / $485 / $540
UNLOCK: 1,050 XP
Description: Twin guns double attack speed.
Effect: Self-explanatory
Airburst Darts
COST: $640 / $750 / $810 / $900
UNLOCK: 1,000 XP
Description: Airburst Darts split into 3 on impact for massively increased popping power.
Effect: Self-explanatory
Ballistic Missile
COST: $1,275 / $1,500 / $1,620 / $1,800
UNLOCK: 17,000 XP
Description: Ballistic Missile seeks its target over any distance and does extra damage to Ceramic and MOAB Class Bloons.
Effect: Self-explanatory
First Strike Capability
COST: $17,000 / $20,000 / $21,600 / $24,000
UNLOCK: 60,000 XP
Description: Ability: a devastating missile strike on the largest bloon on screen. Destroys up to a ZOMG bloon in one go, or many lesser bloons.
Effect: Self-explanatory

Bloons TD 6[]

The Monkey Sub makes a return in BTD6. It can be upgraded as a support tower or as an attack tower. It has also received a substantially greater choice of support/attack capabilities, including an upgrade that supports other Subs.

It is a Military class tower.

Path 1 focuses on range & support. Starting off with it gaining longer range & capability to use another tower's range as its own range, before converting itself into a support tower (which can still unsubmerge and attack using it's guns), capable of decamoing bloons, popping bloons and reducing nearby water tower cooldowns. With it's Tier 5, it has the capability to reduce all cooldowns, and can even affect a hero's levelling speed.

Path 2 focuses on Pierce & later on, dealing huge damage to MOAB Class bloons, starting off with an upgrade to the Sub's pierce & an upgrade that makes all darts pop frozen and lead bloons. Later on it becomes a submarine, capable of shooting missiles that deal extra damage to Ceramics & MOAB Class bloons, with the subs range increasing noticeably. It then gains an ability that can deal massive damage to a target bloon, plus deals splash damage to all bloons in its explosion radius. The Tier 5 retains said ability, can launch it with a shorter cooldown, with its missile attacks being launched at a much faster pace, dealing nearly twice the damage compared to what they did before, and gaining another attack which is passively launches hugely damaging missiles when a MOAB Class bloon enters the screen.

Path 3 focuses on attack speed. Starting off with the Sub gaining another gun, and gaining darts that can split into multiple projectiles. It then gains a third gun, before gaining special darts that can deal extra damage to MOAB Class & Ceramic bloons, much like the middle path does, except with their darts instead of using another projectile. It's Tier 5 further improves its own attack speed, damage, and gives extra damage and pierce to all other subs in its radius.

Path 1[]

Longer Range
COST: $110 / $130 / $140 / $155
Description: Increases attack range.
Effect: Gains +10 range.
Advanced Intel
COST: $425 / $500 / $540 / $600
Description: Allows long range targeting of Bloons in radius of your other towers.
Effect: Allows the Monkey Sub to target any bloon within the range of any tower on screen. Can target Camo Bloons with the range of any tower with direct camo detection.
Submerge and Support
COST: $425 / $500 / $540 / $600
UNLOCK: 2,250 XP
Description: Adds Submerge targeting option that permanently reveals Camo bloons in its radius but does not attack while submerged.
Effect: Self-explanatory
Bloontonium Reactor
COST: $2,125 / $2,500 / $2,700 / $3,000
UNLOCK: 11,000 XP
Description: Submerge to detect Camo, pop Bloons and reduce ability cooldowns of nearby water-based Monkeys by 15%.
Effect: When submerged, creates a radioactive damage zone that pops up to 50 bloons every cycle, decamos much faster, and reduces ability cooldowns of nearby water-based towers by 15%.
COST: $34,000 / $40,000 / $43,200 / $48,000
UNLOCK: 33,000 XP
Description: Reduces ability cooldowns everywhere by 20%. While in radius, heroes earn XP 50% faster and water Monkey ability cooldowns are halved.
Effect: Submerging allows its damage zone to deal 3 damage per cycle instead of 1, reduces ability cooldowns of all towers on screen by 20%, gives nearby heroes with 50% more XP, and nearby water-based towers gain 50% reduced ability cooldowns instead of 15%.

Path 2[]

Barbed Darts
COST: $380 / $450 / $485 / $540
Description: Sub's darts can pop an additional 3 bloons each.
Effect: Darts pop 5 bloons per shot instead of 2.
Heat-tipped Darts
COST: $255 / $300 / $325 / $360
Description: Heat tipped darts allow popping of Frozen and Lead Bloons.
Effect: Self-explanatory
Ballistic Missile
COST: $1,190 / $1,400 / $1,510 / $1,680
UNLOCK: 3,000 XP
Description: Missile seeks target within range and does extra MOAB and Ceramic damage.
Effect: Gains a ballistic missile attack. Missiles fly in the sky and crash onto the target bloon. Missile explosions deal 6 damage to MOAB-class and Ceramics.
First Strike Capability
COST: $11,050 / $13,000 / $14,040 / $15,600
UNLOCK: 20,000 XP
Description: First Strike Ability: A devastating missile strike targeting the largest bloon on screen, plus splash damage.
Effect: Ability shoots a large missile that deals 10,000 damage onto the strongest bloon on screen plus an infinite-pierce splash with 350 damage.
Pre-Emptive Strike
COST: $27,200 / $32,000 / $34,560 / $38,400
UNLOCK: 45,000 XP
Description: Automatically triggers a powerful missile attack whenever MOAB-Class Bloon spawns from the Bloon entrance.
Effect: Every time a MOAB-class bloon enters the screen, it will automatically inflict 750 damage to them. In addition, it gains even stronger and faster ballistic missiles and a faster ability cooldown.

Path 3[]

Twin Guns
COST: $380 / $450 / $485 / $540
Description: Added twin gun doubles attack speed. Enhances Ballistic Missile and Bloontonium Reactor.
Effect: Dart gains 2x attack speed, and the attack speed of alternate attacks increases.
Airburst Darts
COST: $850 / $1,000 / $1,080 / $1,200
UNLOCK: 1,000 XP
Description: Airburst darts split into 3 on impact for massively increased popping power. Further enhances Ballistic Missile and Bloontonium Reactor.
Effect: Main dart now splits into 3 darts on impact, and the attack speed of alternate attacks further increases.
Triple Guns
COST: $935 / $1,100 / $1,190 / $1,320
UNLOCK: 2,750 XP
Description: Adds a third gun for even faster firing.
Effect: Upgrades the attack speed of by 1.5x. Retains the Airburst Darts attack.
Armor Piercing Darts
COST: $2,550 / $3,000 / $3,240 / $3,600
UNLOCK: 10,000 XP
Description: Special AP darts gain increased damage and popping power, plus additional damage to MOAB class Bloons.
Effect: Main dart deals 2 damage on-hit, 4 versus MOAB-class, while airburst darts have 5 pierce per dart instead of 2 and deal 2 damage versus MOAB-class.
Sub Commander
COST: $21,250 / $25,000 / $27,000 / $30,000
UNLOCK: 25,000 XP
Description: Adds extra pierce and damage to Commander and all Subs in its radius.
Effect: All Subs within range will deal double damage and gain +4 pierce.

Total Costs[]

Version History (BTD6)[]

Balance Changes[]

  • Buff 4-x-x Bloontonium Reactor pierce greatly increased (30 → 70).
  • Buff 5-x-x Energizer pierce massively increased (30 → 1000).
  • Buff 5-x-x Energizer now gives a cooldown bonus to all towers on screen, along with a higher bonus to any water towers within radius.
  • Buff x-4-x First Strike Capability price decreased ($20,000 → $13,000).
  • Buff x-x-2+ Airburst darts will now receive benefits from all external sources including the x-x-5 Sub Commander and top path Alchemist buffs.
  • Buff x-5-x Pre-emptive Strike ballistic missile attack bonus damage increased from +4 to +10.
  • Buff x-x-x Base Sub pierce increased from 1 to 2 (This is not added to Airburst darts).
  • Buff 5-x-x Energizer zone radiation damage increased from 1 to 3.
  • Buff x-x-4 Armor Piercing Darts main dart damage increased from 1 to 2, Main dart and Airbursts deal x2 to MOABs for a total of 4 damage on initial hit with 2 damage Airbursts.
  • Buff x-3-x Ballistic Missile fire rate increased from 2s to 1.5s.
  • Buff x-5-x Preemptive Strike's ballistic missile rate increased from 2s to 0.5s.
  • Buff x-x-5 Sub Commander now also buffs itself.
  • Buff x-x-5 Sub Commander now has double the attack rate.
  • Buff x-5-x Pre-emptive Strike price reduced from $40,000 to $35,000.
  • Buff 5-x-x Energizer price reduced from $40,000 to $32,000.
  • Nerf x-4-x First Strike Capability ability damage reduced from 16,700 to 10,000.
  • Nerf x-x-2 Airburst darts pierce of each burst projectile reduced from 3 to 2.
  • Buff x-5-x Pre-emptive Strike price reduced from $35,000 to $32,000.
  • Buff x-5-x Pre-emptive Strike ability cooldown reduced from 60s to 45s.
  • Buff 1-x-x Longer Range range increased from 8 to 10.
  • Buff 4-1-0 Bloontonium Reactor gains 20% increased pierce from 70 to 84.
  • Buff 4-2-0 Bloontonium Reactor gains increased damage to Lead +1.
  • Buff 3-0-1 Submerge and Support Sub gains increased pulse rate 1.5s to 1.275.
  • Buff 3-0-2 Submerge and Support Sub gains increased pulse rate 1.5s to 0.95625.
  • Buff 4-0-1 Bloontonium Reactor gains increased damage pulse rate 0.3s to 0.255.
  • Buff 4-0-2 Bloontonium Reactor gains increased damage pulse rate 0.3s to 0.19125.
  • Nerf x-3-x Ballistic Missile range reduced to 60, matching the regular sub attack.
  • Buff 1-x-x Longer Range increases the range of Ballistic Missile.
  • Buff x-3-x Ballistic Missile price reduced from $1,500 to 1,400.
  • Buff x-3-x Ballistic Missile Ceramic+ damage increased from 5 to 6.
  • Buff x-3-x Ballistic Missile range increased from 42 to 60.
  • Buff 2-3-0 Ballistic Missile attack gains full map coverage.
  • Buff 0-3-1 Ballistic Missile attack rate increased from 1.5s to 1.275.
  • Buff 0-3-2 Ballistic Missile attack rate increased from 1.5s to 0.75.
  • Buff x-x-5 Sub Commander now applies 2x damage to Energizer & Ballistic Missiles.
  • Buff x-x-5 Sub Commander increases Lead bonus of 4-2-0 Bloontonium Reactor from 1 to 2.
  • Buff x-x-5 Sub Commander increases Energizer damage by 2x.
  • Buff x-x-5 Sub Commander increases Ballistic Missile Multi-HP Bloon damage from 6 to 12.
  • Nerf Ballistic Missile range reduced (60 → 50, only +8 range).
  • Nerf 0-3-1 Ballistic Missile crosspath's fire rate reduced from 1.275s to 1.3125s.
  • Nerf 0-3-2 Ballistic Missile crosspath's fire rate reduced from 0.75s to 0.984375s.
  • Nerf Ballistic Missile's splash should no longer hit Camo without Camo Detection.
The cost efficiency of Sub Commander's +5 pierce favored low tiers more than we'd like. Fortunately other paths of sub don't care so much about pierce, so as xx4 AP Darts gives its own large pierce increase we hope lowering the amount of this buff slightly will make driving to T4 more meaningful.
~ Ninja Kiwi
  • Nerf x-x-5 Sub Commander pierce buff reduced from 5 to 4.
Ballistic Missile previously had far too much attack speed added into the crosspath and was rebalanced for parity, but the overall performance loss from this was too much. Better balance will come from the base rate of Ballistic Missile itself.
~ Ninja Kiwi
  • Buff 0-3-0 Ballistic Missile missile reload time reduced from 1.5s to 1.3s. Also carries over crosspaths with Path 3. Also affects Pre-Emptive Strike, from 0.5s to 0.433s.
As Bloontonium Reactor rarely uses up enough pierce that the pierce crosspath would ever matter, a large chunk of this has been moved into the middle crosspath.
~ Ninja Kiwi
  • Nerf 4-0-0 Bloontonium Reactor pierce decreased (70 → 50).
  • Nerf 4-1-0 Bloontonium Reactor pierce decreased (84 → 70).
  • Buff 4-2-0 Bloontonium Reactor pierce increased (84 → 100).
  • Nerf [undocumented] 5-1-0 and 5-2-0 Energizer has less pierce (1,200 → 1,020 for 5-1-0, 1,200 → 1,050 for 5-2-0).
As Airburst Darts alone already gives a huge benefit to the tower regardless of not applying any crosspath buff, some of the attack speed benefit this upgrade gave to 032 Ballistic Missile has instead been moved into the base 030 Missile.
~ Ninja Kiwi
  • Buff 0-3-0 Ballistic Missile missile attack delay reduced from 1.3s to 1.105s.
  • Nerf 0-3-2 Ballistic Missile missile rate buff reduced from 0.75x attack cooldown to 0.90x attack cooldown.
    • Nerf Overall 0-3-2 attack cooldown increased (0.853s to 0.870s).

Bug fixes and other changes[]

  • Monkey Sub darts will now always home even without Advanced Intel.
  • 2-x-x Advanced Intel has been reworked considerably.
  • 2-3-0 Ballistic Missile now gains camo detection from advanced intel.
  • 2-0-2 Airburst Darts now mostly hit Camo Bloons when they should.
  • 0-0-2 Airburst darts will no longer split into the incorrect number of projectiles when the main dart expires because of the round ending.
  • 0-0-2 Airburst Darts are no longer capped to 1 pierce from Monkey Knowledge.
  • 0-5-0 Pre-Emptive Strike can now always hit targets that have been glued.
  • 2-0-0 Advanced Intel should now correctly hit DDT's while under an MIB.
  • 2-0-0 Advanced Intel should no longer fail to correctly home on the first shot fired each round.
  • 0-4-0 First Strike Capability will no longer lock up the game when hitting black bloons.
  • 2-3-0 Ballistic Missile should now correctly have unrestricted range.
  • 0-4-0 First Strike should no longer crash the game when destroying a BAD.
  • 5-0-0 Energizer Sub should correctly apply bonus XP to heroes.
  • 4+-0-0 buffs now apply correctly to other towers.
  • 2-x-x Advanced Intel no longer waits until the center pixel of blimps comes into radius before attacking.
  • 3+-x-x Monkey Subs can now be overclocked by Engineers.
  • Placing a Sub Commander within range of a Village will no longer cause the Sub Admiral Monkey Knowledge to fail.
  • 2-x-x Advanced Intel no longer permanently breaks after being placed back down from a Door Gunner. Note that intel itself still can not apply when used as a Door Gunner.
    • According to NK developer Rohan, this is due to performance issues.
  • 2-x-x Sub portrait has been corrected to fit the model better.
  • x-5-x Pre-Emptive Strike description "reworded as the effect is very different to 'MOAB Assassin'".
  • Sub Ducky Pet released.
  • Change x-4-x First Strike Capability Description changed to reflect the presence of splash damage in the ability.
    • Changed from "First Strike ability: A devastating missile strike on the largest Bloon on screen." to "First Strike Ability: A devastating missile strike targeting the largest bloon on screen, plus splash damage."
    • Undocumented in Patch Notes.
  • x-5-x Pre-Emptive Strike corrected a typo for Pre-emptive Strike's description, where "missile" was mispelt as "missle".
  • Resolved some issues with x-x-5 Sub Commander not always correctly buffing the damage of x-5-x Pre-emptive Strike.
  • Monkey Sub x-x-1 animation states should no longer fall out of sync.
  • Nerf 2-x-x Advanced Intel no longer gains camo detection from Lvl 1 Etienne or Dartling.
  • 3-x-x & 4-x-x Subs have had some optimizations to unnecessary code.
  • 4-x-x Sub correctly layers assets onto regrow Bloons again.
  • 5-x-x Sub inconsistencies resolved with how buffs were applying.
  • Change [visual change] Submerge and Support should no longer be possible to disconnect tower location from visible model.

Update History (BTDB Mobile)[]

With exception of the popular Airburst Darts upgrade, the Monkey Sub is fairly balanced. The 0/2 Airburst Darts Sub is still a pretty popular starting tower for those with Monkey Sub and water-dominant tracks, especially on Water Hazard, even when nerfed to a higher price.
  • Nerf Airburst Darts price increased ($750 → $1000).
  • Nerf Overall fire rate decreased (1.59 shots per second → 1.31).
  • Nerf Bloontonium Reactor price increased ($2500 → $2800).
  • Change Bloontonium Reactor now automatically switches the tower into submerged mode upon purchase.
  • Nerf Fixed a bug where Bloontonium Reactor's water tower cooldown decrease stacked with any other Reactor in range. (Still works in BTD5 and BMC).
  • Nerf Tower price increased ($350 → $400).
  • Buff Base tower and Barbed Darts pierce increased (1 → 2, 3 → 4).


Monkey Subs must be placed on water but once in place they shoot homing darts. Can be upgraded to shoot at Bloons in the radius of any other Monkey and can be set to submerge and become a support unit.
~ BMC Description
Get to your battle stations, the Monkey Sub is in Bloons TD 5! The Monkey Sub has surfaced! With its array of powerful weaponry, support capabilities and functional upgrades the Sub is ready to join your Monkeys in the fight against the Bloons. Deploy the sub in the nearest bit of water and see how far you get!
~ July 23rd, 2015 "Monkey Sub is here!" description
Water based tower that shoots homing darts. Can upgrade to shoot at Bloons in the radius of any other tower. Can also upgrade to submerge and become a support tower.
~ Bloons TD 5 Description


  • First Strike Capability is the first and currently only ability to be able to pop a whole ZOMG in one shot in BTD5.
  • The submerged Bloontonium Reactor can work similarly to a weaker but bigger and camo-revealing Ring of Fire.
  • If a bloon is poppable by another tower, it can be popped by the Sub, with the upgrade Advanced Intel. This means that, like the Spike Factory and Ninja Monkey, it can pop Camo Bloons without either having an innate ability, by being in the range of a 0,2 or higher Monkey Village, or having an upgrade that says so.
    • Also, since the Monkey Village has a range of effect, the Sub is able to target bloons within that building's range as well.
    • A glitch can appear in BTD5 Mobile where a sub with 2/x on strong will attack Ceramic Bloons over MOAB-class bloons if the MOABs are only in a Glue Gunner's range, if also set to strong. The subs though, can attack the MOABs if no lower bloon rank exists with the glue gunner's range.
  • It does not do significant damage to high numbers of MOAB class bloons without the help of First Strike Capability.
  • This is one of three towers where Camo Bloon detection for the tower itself is a third tier upgrade. The others being the Mortar Tower and the Monkey Engineer. (Although technically, none of those towers can hit camo, they just remove it.)
  • This is the second tower that can be placed in water, the first one being the Monkey Buccaneer.
  • Interestingly enough, the Advanced Intel upgrade works on Heli Pilots, meaning that a Monkey Sub can shoot anywhere with Advanced Intel if the Heli Pilot is in Pursuit mode.
    • This is no longer true in BTD6, where it only shoots near the Heli Pad.
  • A bunch of 2/3 Monkey Subs can withstand many Ceramic Bloons.
  • An 1/1 or 2/2 Monkey Sub has an appearance that combined 1/0 and 0/1 or 2/0 and 0/2 together.
  • A Monkey Sub with an Advanced Intel upgrade works well with a Village with Bigger Beacons as the range of the tower be as well the range of the Village.
  • In BMC Mobile, there is a special mission where the player receives four 1/1 Subs and a 2/4 Sub, which is broken but can be used in gameplay by repairing it for $8,000.
    • However, the mission is nearly impossible without the Broken Sub repaired in time, since a ZOMG will appear on Round 15 along with other MOABs. If repaired in time, the player must use the ability at the very start of the round, because the ZOMG will appear first.
  • There is a striking resemblance of the captain of the sub looking like the commander of the Warhammer 40,000 tank, once one upgrades to Barbed Darts, it looks like the captain wants to get close, so they can hit them with their dart.
  • Monkey Sub can hit bloons within the range of a Monkey Farmer, despite the farmer having no popping power.
  • In BTD5 Flash, a glitch with the Bloontonium Reactor is possible: if a Monkey Sub is upgraded to Bloontonium Reactor while in the radius of another water-based tower, the newly upgraded sub may remain at a 3/x tower rather than a 4/x tower, but the money will still be lost, and upgrading it now becomes impossible.
  • On the Flash version, the Monkey Sub tier 4 upgrades are unlocked at Rank 19 while the tower unlocks at Rank 20. Probably not intended.
  • If under the influence of a x/2 or a x/3 Monkey Village, the Ballistic Missiles do not affect Camo Bloons except if they are in the range of a tower. This glitch is also occured in BTD5 Flash.
  • No specialty buildings in BTD5 Mobile have a negative effect in this tower as it was added later by itself.
    • The Monkey Engineer and the Bloonchipper were added together and negatively effect each other.
  • A 2/0 Monkey Sub with a 1/2 Sniper Monkey can be useful in the early rounds but be careful as bloons may leak if you leave the Path 2 unupgraded. However, this does not work in BTD5 Mobile as the Advanced Intel range of Sniper is a small area around it.
  • When the tower was added in BTD5 Mobile, the player needed to pop 2 million bloons to unlock the tower and the bonus tracks. This was later changed to 250,000.
  • In Bloons TD 5 Mobile / Bloons TD 5 Steam the description haves a spell error. Saying "Incuding" while it was meant to be "Including". The full description for that one was "Incuding the ability to submerge and become a support tower".