Oshawott locations — where to catch

In Blueberry Academy (Scarlet & Violet – The Indigo Disk)

• Polar Biome — Walk

In Hisui (Legends: Arceus)

• Space-time distortions — Walk

Other games (3)

• Omega Ruby / Alpha Sapphire (Gen 6): Hoenn Route 101
• Black 2 / White 2 (Gen 5): Aspertia City
• Black / White (Gen 5): Nuvema Town

Oshawott — full Pokédex entry