Legendary Pokémon

As expected, Pokemon FireRed and LeafGreen allow you to capture the classic legendary Pokemon from Red and Blue, along with some familiar faces from Gold and Silver. Don't knock them out or run from them though, as these fabled Pokemon won't reappear again after.

Some tips for catching these: bring lots of Repels en route to finding the Pokemon, along with strong Pokeballs that best suit the situation. It is recommended you save in front of the Pokemon too, should the worst happen and you defeat them (or are defeated by them).

Stationary Pokémon

#144 Articuno

Location: Seafoam Island

Method:
The stunning Ice/Flying legendary bird Pokemon, Articuno appears at the bottom of Seafoam Islands after a rigorous rock-moving puzzle involving Strength and Surf.

Articuno
Level 50
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Seafoam Island. Caught at Lv. 50
Mist
Agility
Mind Reader
Ice Beam
#145 Zapdos

Location: Power Plant

Method:
The shockingly powerful Electric/Flying legendary bird Zapdos appears at the end of the Power Plant near the exit.

Zapdos
Level 50
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Power Plant. Caught at Lv. 50
Thunder Wave
Agility
Detect
Drill Peck
#146 Moltres

Location: Mt. Ember

Method:
Moltres, the Fire/Flying legendary bird, is the only Pokemon to leave its original home from Red and Blue. This time you can find it residing at the volcanic Mt. Ember on One Island, after a Strength boulder puzzle.

Moltres
Level 50
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Mt. Ember. Caught at Lv. 50
Fire Spin
Agility
Endure
Flamethrower
#150 Mewtwo

Location: Cerulean Cave

Method:
The strongest Pokemon, Mewtwo, makes its home at the end of the treacherous Cerulean Cave. This unknown dungeon cannot be accessed until after you've received the National Dex and requires Surf, Rock Smash, and Strength to navigate. Get its HP down carefully and avoid burning, confusing, or poisoning it so you don't knock it out accidentally. Sleep and paralysis work well.

Mewtwo
Level 70
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Cerulean Cave. Caught at Lv. 70
Swift
Recover
Safeguard
Psychic

Event Pokémon

#249 Lugia

Location: Navel Rock

Method:
The legendary birds of the Johto region take residence in the eighth Sevii Island, Navel Rock. To get there, you need the MysticTicket. Inside the island there are two paths; the one on the left takes you up a long flight of stairs to meet Ho-oh at the summit, whereas the one on the right takes you down to the heart of the island underwater to meet Lugia. Be prepared for a tough battle - both are at Level 70.

Lugia
Level 70
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Navel Rock. Caught at Lv. 70
Recover
Hydro Pump
Rain Dance
Swift
#250 Ho-Oh

Location: Navel Rock

Method:
The legendary birds of the Johto region take residence in the eighth Sevii Island, Navel Rock. To get there, you need the MysticTicket. Inside the island there are two paths; the one on the left takes you up a long flight of stairs to meet Ho-oh at the summit, whereas the one on the right takes you down to the heart of the island underwater to meet Lugia. Be prepared for a tough battle - both are at Level 70. Once you capture Ho-oh, don't forget the Sacred Ash that lay hidden where it was standing.

Ho-Oh
Level 70
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Navel Rock. Caught at Lv. 70
Recover
Fire Blast
Sunny Day
Swift
#386 Deoxys

Location: Birth Island

Method:
For the first time ever you can catch the final Pokemon of the Hoenn Pokedex, Deoxys, provided you've got the AuroraTicket item. Deoxys is fittingly found on the last Sevii Island, Birth Island - but only after you complete a rather unique puzzle. This puzzle involves chasing a black triangle around the island and talking to it until it becomes red hot, after which Deoxys will emerge and attack. Perhaps unusually, Deoxys is the lowest leveled Legendary Pokemon at just Level 30, so be careful not to knock it out.

After you catch Deoxys it will revert to either its Attack Forme in FireRed or its Defense Forme in LeafGreen. These cannot be changed without trading, and only then as long as the Pokemon is in the game - however, stats will still be calculated accordingly for link battles. That is to say, for example, that a Deoxys on Emerald would have its Speed Forme stats when fighting against FireRed (and vice versa).

Deoxys
Level 30
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Birth Island. Caught at Lv. 30
Taunt
Pursuit
Psychic
Superpower
Deoxys
Level 30
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Birth Island. Caught at Lv. 30
Knock Off
Spikes
Psychic
Snatch

Roaming Pokémon

#243, 244, 245 - Raikou, Entei, Suicune

Location: Kanto

Method:
Making their debut in the Kanto region are the legendary dog trio of Johto, who once again take to the grasses of the countryside as roaming Pokemon. You will only encounter one per game and its contingent upon which starter Pokemon you picked; that is, the legendary with the type advantage will appear - Entei for Bulbasaur, Suicune for Charmander, Raikou for Squirtle. You must also have cleared Team Rocket out of the Sevii Islands to trigger their appearence. As with all roaming Pokemon their location is totally random the first time, and they will attempt to escape on the first turn of battle. This means you must use a trapping move such as Block to be able to fight them. A word of caution, though - due to a glitch, Entei and Raikou (but not Suicune) will sometimes use Roar if trapped and can never be seen again. For this reason it may be best to save your Master Ball to use on these incredibly difficult Pokemon.

Raikou
Level 50
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Location of Capture. Caught at Lv. 50
Thundershock
Roar
Quick Attack
Spark
Entei
Level 50
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Location of Capture. Caught at Lv. 50
Ember
Roar
Fire Spin
Stomp
Suicune
Level 50
OT:Yours
ID:Yours
Ability:Pressure
Hold Item:
None
??? Nature.
Date of Receiving
Location of Capture. Caught at Lv. 50
Bubblebeam
Rain Dance
Gust
Aurora Beam