Mamoswine locations — where to catch

In Hisui (Legends: Arceus)

• Avalanche Slopes — Walk
• Avalugg's Legacy — Walk

Other games (4)

• Sword / Shield — The Isle of Armor (Gen 8): Frigid Sea, Giant's Bed, Slippery Slope, Snowslide Slope
• Sword / Shield (Gen 8): Stony Wilderness
• Black 2 / White 2 (Gen 5): Giant Chasm
• Black / White (Gen 5): Giant Chasm

Mamoswine — full Pokédex entry