Yanma locations — where to catch

In Kitakami (Scarlet & Violet – The Teal Mask)

• Infernal Pass — Walk
• Kitakami Wilds — Walk
• Oni Mountain — Walk
• Timeless Woods — Walk
• Wistful Fields — Static Encounter

In Hisui (Legends: Arceus)

• Droning Meadow — Walk
• Gapejaw Bog — Walk
• Heavenward Lookout — Walk
• Ursa's Ring — Walk

In Sinnoh (Diamond, Pearl & Platinum)

• Great Marsh — Walk

In Johto & Kanto (HeartGold & SoulSilver)

• Route 35 — Walk

In Sevii Islands (FireRed & LeafGreen)

• Ruin Valley — Walk

In Johto & Kanto (Gold, Silver & Crystal)

• Route 35 — Walk

Other games (5)

• Brilliant Diamond / Shining Pearl (Gen 8): Great Marsh
• X / Y (Gen 6): Kalos Route 10
• Black 2 / White 2 (Gen 5): Pinwheel Forest, Unova Route 3
• Black / White (Gen 5): Route 14
• Colosseum (Gen 3): Pyrite Bldg, Snagem Hideout

Yanma — full Pokédex entry