Where to catch Dratini

In Paldea (Scarlet & Violet)

• Casseroya Lake — Walk
• North Province (Area Two) — Walk
• South Province (Area Six) — Walk

In Johto & Kanto (Gold, Silver & Crystal)

• Dragon's Den — Good Rod, Super Rod, Surf, Walk, Gift
• Route 45 — Good Rod, Super Rod

In Kanto (Red, Blue & Yellow)

• Celadon City — Gift
• Safari Zone — Super Rod, Walk

Dratini — full Pokédex entry