seafoam island
You cannot catch Articuno in Pokemon Sapphire, but you can trade it from FireRed or LeafGreen.
You can't catch articuno in pearl unless you migrate it from firered or leafgreen.
u can catch it when u catch articuno moltries and zapdos
It's at lvl 50.
You must migrate from FireRed/LeafGreen or trade from Platinum.
mewtow zapdos moltres articuno mew entei raikou suicune
Articuno is found in the Seafoam Islands. Be sure to save before you battle, and bring lots of pokeballs. Articuno can be tricky to catch.
If you don't get it from seafoam islands you must have a friend trade you one from there leafgreen or firered or get one from Pokemon xd gale of darkness.
Lots of ultra balls to catch it, a Pokemon around level 50, Pokemon that know surf and strength.
Weaken it to red HP, paralyze it or make it sleep then use many ultra balls.
The only way I'm familiar with besides the Action Replay is to catch it in Leafgreen or FireRed and then migrate it.
Moltres, zapados, and articuno are the three main legendaries in leaf green/fire red