Weak toGrassElectric ×1.6

Attacker	Type	Moveset	DPS
Regieleki	Electric	Lock OnThunder CageLegacy	46.3
Zeraora	Electric	Volt SwitchPlasma Fists	39.7
Kartana	GrassSteel	Razor LeafLeaf Blade	39.6
Zekrom	DragonElectric	Charge BeamFusion BoltLegacy	38.8
Xurkitree	Electric	Thunder ShockDischarge	38.4
Roserade	GrassPoison	Magical LeafLeaf Storm	33.8
Eternatus	PoisonDragon	Poison JabDynamax CannonLegacy	33.6
Deoxys	Psychic	Charge BeamThunderbolt	33.4
Electivire	Electric	Thunder ShockWild Charge	33.2
Zarude	DarkGrass	Vine WhipPower Whip	33.1
Rillaboom	Grass	Razor LeafFrenzy PlantLegacy	32.7
Raikou	Electric	Volt SwitchWild Charge	32.3

Rainy boosts the Electric attacks above. Rainy boosts Shellder.

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

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

Questions people ask

What is Shellder weak to in Pokémon GO?

Shellder takes 1.6 times from Grass and Electric.

What's the best counter to Shellder?

Regieleki with Lock On and Thunder Cage, worth 46.3 damage per second against Shellder's own defense. The full ranking is above.