Weak toPoisonSteel ×1.6

Attacker	Type	Moveset	DPS
Eternatus	PoisonDragon	Poison JabSludge Bomb	41.0
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	40.2
Tinkaton	FairySteel	Fairy WindGigaton HammerLegacy	39.1
Naganadel	PoisonDragon	Poison JabSludge Bomb	38.9
Lucario	FightingSteel	Bullet PunchMeteor Mash	37.1
Nihilego	RockPoison	Poison JabSludge Bomb	36.9
Roserade	GrassPoison	Poison JabSludge Bomb	36.1
Dialga	SteelDragon	Metal ClawIron Head	35.6
Munkidori	PoisonPsychic	Poison JabSludge Bomb	35.4
Regigigas	Normal	Hidden PowerCrush GripLegacy	34.9
Genesect	BugSteel	Metal ClawMagnet Bomb	34.8
Revavroom	SteelPoison	Poison JabGunk Shot	34.0

Snow boosts the Steel attacks above. Overcast boosts Swirlix.

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

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

Questions people ask

What is Swirlix weak to in Pokémon GO?

Swirlix takes 1.6 times from Poison and Steel.

What's the best counter to Swirlix?

Eternatus with Poison Jab and Sludge Bomb, worth 41.0 damage per second against Swirlix's own defense. The full ranking is above.