Swift Swim is an Ability that doubles the Speed of a Pokémon while it is raining.
The use of Swift Swim in combination with a Pokémon with the Drizzle Ability can be restricted by certain battle rules.
- Drizzle-Swim Clause: A team cannot have a Pokémon with the Drizzle Ability and another Pokémon with the Swift Swim Ability.
- Weather Ability Clause: A team cannot have a weather-setting Ability and an Ability that boosts Speed when that weather is active. This includes the combinations of Drizzle and Swift Swim, Drought and Chlorophyll, and Sand Stream and Sand Rush.