Weak toFightingBugGrassElectricFairy ×1.6

Attacker	Type	Moveset	DPS
Regieleki	Electric	Lock OnThunder CageLegacy	41.3
Lucario	FightingSteel	Force PalmAura SphereLegacy	37.0
Pheromosa	BugFighting	Bug BiteFocus Blast	35.9
Kartana	GrassSteel	Fury CutterLeaf Blade	35.7
Zeraora	Electric	Volt SwitchPlasma Fists	35.5
Zekrom	DragonElectric	Charge BeamFusion BoltLegacy	34.6
Xurkitree	Electric	Thunder ShockDischarge	34.2
Terrakion	RockFighting	Double KickSacred SwordLegacy	33.7
Blaziken	FireFighting	CounterAura Sphere	33.4
Tapu Koko	ElectricFairy	Volt SwitchNatures MadnessLegacy	32.5
Breloom	GrassFighting	Force PalmGrass KnotLegacy	31.7
Enamorus	FairyFlying	Fairy WindDazzling Gleam	31.2

Rainy boosts the Electric attacks above. Fog and Rainy boost Greninja.

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

Greninja's moveset, CP and shiny All counters Raid board

Questions people ask

What is Greninja weak to in Pokémon GO?

Greninja takes 1.6 times from Fighting, Bug, Grass, Electric and Fairy.

What's the best counter to Greninja?

Regieleki with Lock On and Thunder Cage, worth 41.3 damage per second against Greninja's own defense. The full ranking is above.