Weak toPoisonGround ×1.6

Attacker	Type	Moveset	DPS
Eternatus	PoisonDragon	Poison JabSludge Bomb	28.0
Naganadel	PoisonDragon	Poison JabSludge Bomb	26.6
Groudon	Ground	Mud ShotPrecipice BladesLegacy	26.5
Nihilego	RockPoison	Poison JabSludge Bomb	25.2
Excadrill	GroundSteel	Mud SlapEarthquake	25.2
Mamoswine	IceGround	Mud SlapHigh Horsepower	24.7
Roserade	GrassPoison	Poison JabSludge Bomb	24.7
Munkidori	PoisonPsychic	Poison JabSludge Bomb	24.2
Regigigas	Normal	Hidden PowerCrush GripLegacy	23.9
Rhyperior	GroundRock	Mud SlapEarthquake	23.9
Garchomp	DragonGround	Mud ShotEarthquake	23.6
Landorus	GroundFlying	Mud ShotEarth Power	23.5

Overcast boosts the Poison attacks above. Overcast and Rainy boost Tapu Koko.

Level 40, 15 attack IV, costed against Tapu Koko's own defense and typing, one per evolution family.

Tapu Koko's moveset, CP and shiny All counters Raid board

Questions people ask

What is Tapu Koko weak to in Pokémon GO?

Tapu Koko takes 1.6 times from Poison and Ground.

What's the best counter to Tapu Koko?

Eternatus with Poison Jab and Sludge Bomb, worth 28.0 damage per second against Tapu Koko's own defense. The full ranking is above.