Lucario locations — where to catch

In Lumiose City (Legends: Z-A)

• Hotel Z — Static Encounter
• Wild Zone 20 — Static Encounter

In Paldea (Scarlet & Violet)

• East Province (Area Three) — Walk
• Glaseado Mountain — Walk, Static Encounter
• North Province (Area One) — Walk
• North Province (Area Two) — Walk
• Tagtree Thicket — Walk

In Kitakami (Scarlet & Violet – The Teal Mask)

• Kitakami Wilds — Walk
• Timeless Woods — Walk

In Hisui (Legends: Arceus)

• Icebound Falls — Walk
• Snowfall Hot Spring — Walk

Other games (5)

• Sword / Shield — The Isle of Armor (Gen 8): Brawlers' Cave, Courageous Cavern, Roaring-Sea Caves
• Sword / Shield (Gen 8): Dusty Bowl, Giant's Seat, Hammerlocke Hills, North Lake Miloch, Rolling Fields, Stony Wilderness
• Ultra Sun / Ultra Moon (Gen 7): Poni Grove
• Sun / Moon (Gen 7): Poni Grove
• X / Y (Gen 6): Tower Of Mastery

Lucario — full Pokédex entry