Slowking's great special bulk, typing, and combination of Future Sight, Teleport, and Regenerator make it a decent specially defensive pivot in the metagame. It checks various dangerous threats such as Tapu Lele and Heatran, and it can easily set up advantageous situations for its teammates like Mega Lopunny and Weavile with Future Sight and Teleport. However, it is a specially bulky Water-type that cannot handle Ash-Greninja at all, and it's completely outclassed by Slowbro and Galarian Slowking in the Future Sight department. Its low Defense and Dark weakness leave it vulnerable to physical attackers like Mega Lopunny, Garchomp, and Pursuit users like Weavile and Tyranitar, even though all of these fear Scald. Thus, Slowking struggles to fit on teams, and it's almost entirely outclassed by other Water-types such as Slowbro, Toxapex, and Tapu Fini. Future Sight prevents Pokemon such as Toxapex, Clefable, and Kommo-o from switching in safely on Slowking's teammates like Mega Charizard Y and Mega Lopunny until it lands, often leading to checkmate situations. Teleport grants free switches in for Slowking's frail teammates like Weavile and Mega Medicham. Slack Off and Regenerator make it a good long-term check to threats like Heatran and Tapu Lele. Heavy-Duty Boots cancels entry hazard damage, letting it pivot more easily. The given EV spread lets it tank two Moonblasts from Choice Specs Tapu Lele from full health.

Slowking fits best on balance and bulky offense teams. Pokemon like Ash-Greninja, Mega Lopunny, Mega Charizard Y, and Weavile greatly appreciate Slowking's Future Sight support, which can let them overwhelm their checks like Toxapex, Kommo-o, and Clefable, as well as the free switch-in opportunities from Teleport. It being a Water-type that cannot check Ash-Greninja makes Pokemon such as Tapu Bulu, Kommo-o, and Amoonguss mandatory partners. Slowking is very vulnerable to Grass-types like Rillaboom, Serperior, and Kartana, so good checks to these like Corviknight, Zapdos, and Tangrowth make for good teammates. Good checks to Dark-types like Weavile, Hydreigon, Tyranitar, which can overwhelm or Pursuit trap Slowking, include Kommo-o, Corviknight, and Clefable. Pokemon such as Clefable, Mega Lopunny, and Ferrothorn appreciate Slowking checking Tapu Lele and Heatran. Amoonguss, Gliscor, and Ferrothorn can handle Electric-types for Slowking. Finally, Slowking is easily overwhelmed by physical attackers like Mega Lopunny, Mega Mawile, and Garchomp due to its mediocre physical bulk, but teammates like Corviknight and Landorus-T can handle these threats well.