Ability · Gen 4 · 2 Pokémon
Slow Start
On switch-in, this Pokemon's Attack and Speed are halved for 5 turns.
Slow Start was introduced in Generation 4. 2 Pokémon and forms can have it (1 as a hidden ability).
Best Pokémon with Slow Start
Ranked by usage in public Pokémon Showdown battles (Champions VGC first, then National Dex OU, SV OU and Champions Singles), with how many of each Pokémon's sets actually run Slow Start.
Pokémon with Slow Start
As a regular ability (1)
As a hidden ability (1)
VaroomSlow Start FAQ
What does Slow Start do?
On switch-in, this Pokemon's Attack and Speed are halved for 5 turns.
Which Pokémon have Slow Start?
2 Pokémon and forms can have Slow Start, 1 of them only as a hidden ability: Regigigas and Varoom.
Is Slow Start a hidden ability?
It depends on the Pokémon. Varoom has it as a hidden ability, while Regigigas can have it as a regular ability.
What are the best Pokémon with Slow Start?
By competitive usage, the most used Pokémon that can have Slow Start are Regigigas (#254 in SV OU, 100% run Slow Start).
Effect text from Pokémon Showdown (MIT); which Pokémon have it from Showdown's Pokédex, cross-checked against PokéAPI. Unofficial fan site.