how to catch deoxys?

Deoxys is not in this game. Only by trading or Action Replays

Deoxys WAS available in the game, but is no longer catchable in this game. You have to Trade it from are/S/E/LG or use Gameshark or Action Replay.

There was once a Mystery Gift giving a rainbow pass. The rainbow pass could be used to get from vermillion city to Birth Island. On birth island Deoxys would be waiting in some sort of cone shaped thing.
Sadly the Mystery Gift is no longer given out.

you can get Deoxys in fire red these are all the ways how * You need to achieve the Aurora Ticket.

* Go to a mart and type in to the quartinary "link together with all."

* To get Deoxys on Pokemon FireRed: It's easy to catch Deoxys. You must go to an Island called Birth Island. It is the triangleish one on the map of Islands One, Two and Three. But sadly, the only way to get there is to compete in a Nintendo Special Event or if you have one, use a GameShark SP or a normal GBA GameShark depending on what console you have.

* To get Deoxys, you must have a gameShark or you can unite with a friend, put in the Mystery Gift and you will have the Aurora Ticket.

* Alright everyone this is an actual cheat to getting Deoxys on FireRed. First get these Pokemon in your party: Articuno, Zapdos, Moltres, Raikou, Suicune and Entei. Then beat Gary once again. After you start your game again, Fly to Cerulean and walk over to Bill's house and show him your rare Pokemon. He will commend you for catching these rare Pokemon and give you an Aurora Ticket. Then go to Birth Island and solve the puzzle in the middle of the island. Then claim your Deoxys.

* Go to Professor Oak after defeating the Elite 4 five or six times. He will give you the Aurora Ticket and the Mystic Ticket and then you can go to Islands 8 and 9.

* You have to have the Wonder Gift to obtain the Aurora Ticket. You unlock the Wonder Gift by entering this into any marts paper at the side link together with all. You need to have beaten the Elite 4. To do it, you save your game go on it just underneath new game and go on the Wonder Gift. Tthen talk to a man with a green hat in any second floor of a Poke center. He will give you the ticket to get to Birth Island, to do a puzzle where he is to unlock a level 70 Deoxys.

* The only way to get Deoxys is by using the Mystery Gift next to a Wonder Spot (in a Nintendo Event) with you Wireless adapter connected Then you can get an Aurora Ticket and go to Island 9, or using GameShark or Code Break! (this is aplied only on FireRed, Leaf Green and Emerald). If someone knows how to get Deoxys, prove it by writing the Pokedex inscriptions.

* You get it by either going to a Pokemon Nintendo Event (all over for the time being) or retail stores (to be determined). I heard you can get the Aurora Ticket through a friend who already has it (through Mystery Gift somehow). Then how do you get Mystery Gift? On the counter in any normal Pokemart there is a memo pad. If you type Link togeter with all you get the Mystery Gift.

* Go to 4 island, go to the mart and type 'link together with all'. Save and turn off your GBA. Once you turn it on again, Mystery Gift will appear. Link with Wireless adapter to a friend. You get a ticket and sail to the Islands.

* Alrighty, people. This is how you actually get Deoxys. Go to the Pokecenter on 5 island. Then use your Wireless adapter and go upstairs. (this is actually a bug in the game that you abuse.) You have to go into the union room (yes you can enter alone.) and then put a Rayquazza level 75 up for Trade for a psychic type Pokemon. Then if you are lucky, an old man will appear and tell you that he knows where you can get a really rare psychic Pokemon! He will tell you to go to a Pokemart and
In the notepad type in "link together with all" and that will be your ticket to getting a really rare Pokemon. This bug only occurs in one out of every ten Pokemon games. To find him is like finding a shiny Pokemon.

* First you must get the Aurora Ticket and then go to Birth Island and walk in the triangle. Go up to Deoxys and battle him and POOF! You got yourself a Deoxys.

* To get him go to Birth Island With the Aurora Ticket (this is the real way to get Deoxys).

* Fly to Cinnabar, then go to Pewter City and talk to the man you helped a long time ago. The guy who needed coffee. Talk to him and say no, then fly back to Cinnabar Island use Surf up and down where Blains Gym is. On the coast not the water, until you encounter a Missingo. YOU CAN ALSO DO THE SAME STEP, JUST GO ONE SPACE OF THE COAST GO UP AND DOWN THEN YOULL FIND A LEVEL 100 MARAWAK!

* This is a list of warp codes for Action Replay. Note all is Pokemon Emerald only walk throught a door and viola you're there. M: d8bae4d9 4864dce5 a86cdba5 19ba49b3 a57e2ede a5aff3e4 1c7b3231 b494738c; Enable code: 653C743B 4B626426 Southern Island: 7703F025 00394020. Faraway Island (Mew): 82CBD483 7B9D8E0B; Birth Island (Deoxys): E5AC0043 E1C4C8F0; Navel Rock (Lugia and Ho-Oh): B5B9E5C0 B11CE872; Old sea map in PC: 5B1CB4D7 10FA9D05

The deoxy can find in Viridian Forest reagularly

Mastercode 1:
000014D1 000A
1003dae6 0007

Master code 2: (For GBA4iOS users only)
4D83B1BF E0F5F507
8E883EFF 92E9660D
B6C5368A 08BE8FF4
90B4977C C0151DC2

Note: For GBA4iOS users, you need to have both Master code 1 and 2 activated together to get it to work.

Pokemon code:

Articuno
83007CEE 0090

Zapdos
83007CEE 0091

Moltres
83007CEE 0092

Dratini
83007CEE 0093

Dragonair
83007CEE 0094

Dragonite
83007CEE 0095

Mewtwo
83007CEE 0096

Jirachi
83007CEE0199

Regirock
83007CEE0191

Regice
83007CEE0192

Registeel
83007CEE0193

Groudon
83007CEE0195

Mew (won’t obey)
83007CEE 0097

Deoxys (won’t obey)
83007CEE 019A

Entei
83007CEE 00F4

Lugia
83007CEE 00F9

Ho-Oh
83007CEE 00FA

Rayquaza
83007CEE 0196