Weak toPoisonSteel ×1.6

Attacker	Type	Moveset	DPS
Eternatus	PoisonDragon	Poison JabSludge Bomb	24.9
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	24.5
Tinkaton	FairySteel	Fairy WindGigaton HammerLegacy	23.8
Naganadel	PoisonDragon	Poison JabSludge Bomb	23.7
Lucario	FightingSteel	Bullet PunchMeteor Mash	22.6
Nihilego	RockPoison	Poison JabSludge Bomb	22.5
Roserade	GrassPoison	Poison JabSludge Bomb	22.0
Dialga	SteelDragon	Metal ClawIron Head	21.7
Munkidori	PoisonPsychic	Poison JabSludge Bomb	21.6
Regigigas	Normal	Hidden PowerCrush GripLegacy	21.3
Genesect	BugSteel	Metal ClawMagnet Bomb	21.2
Revavroom	SteelPoison	Poison JabGunk Shot	20.7

Snow boosts the Steel attacks above. Overcast boosts Sylveon.

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

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

Questions people ask

What is Sylveon weak to in Pokémon GO?

Sylveon takes 1.6 times from Poison and Steel.

What's the best counter to Sylveon?

Eternatus with Poison Jab and Sludge Bomb, worth 24.9 damage per second against Sylveon's own defense. The full ranking is above.