Tutorial : Transfer Pokémons from GBA to last gen.
Here's a tutorial I've already post to Arqade. I'll repost/update it here as it needs to be refreshed.
I'll try to update it in the future if methods change
Let's start
First of all, it's not trade, it's a transfer you'd be doing, I would say one way transfer (always from the oldest gen to the newest).
Even if it's not the question keep in mind that GB to GBA is not possible at all.
Here's the full process to make it from GBA to Nintendo 3DS (by using Nintendo DS)
First step : GBA to DS
I will sum up the method describe in this tutorial. (it's the same process with Sapphire, Fire Red, Leaf Green).
You need a Nintendo DS with GBA port (DS or DS lite), this means that Nintendo DSi are not compatible
This part needs to be done in two process:
- GBA -> Diamond/Pearl/Platinum or Soul Silver/Heart Gold
Once you have finished the DS Game (D/P/Pl or SS/HG), you need to go to the Pal Park (in the game) while the GBA game are inserted inside the DS, then you will be allowed to transfer 6 Pokémons every 24 hours (there's a trick on the internet to bypass this limit).
Compatible GBA games are : Ruby, Saphyr, Emrald, Leaf green, Fire red
- Diamond/Pearl or Soul Silver/Heart Gold -> Black & White or Black 2 White 2
Now that you have all your Pokémon from GBA inside (D/P/Pl or HS/GS), you need to transfer it to Pokémon Black/White or Pokémon Black 2/White 2. Once you have finished the DS Game (B/W or B2/W2), you need to go to the Pokémon Tansfer Lab. Fortunately there's no more time limit this time.
for this step you need two consoles that can read Nintendo DS games (Nintendo DS or 3DS)
Second step : DS to 3DS
This step is much easier, I will sum up the process describe in the official Poké Bank site by Nintendo.
On the 3DS you need to download (via Nintendo eshop) a game called Pokémon Bank. This game has a subscription fee of $5 a year. (If you like Pokémon games, it's worth the price). In this procedure you can pay the price only for one year. Pokémon Bank is a system that allow you to store your Pokémon on the internet.
When you have Pokémon Bank, you will be able to download another free app (with no subscription) called Poké Transporter. This one will allow you to transfer any Pokémon from B/W or B2/W2 to the Pokémon Bank. It's really easy and much simpler than before.
Once your Pokémon are in the Pokémon Bank, you can transfer them to one of the 3DS version of Pokémon : Pokémon X, Pokémon Y, Pokémon Omega Ruby, Pokémon Alpha Sapphire, Pokémon Sun, Pokémon Moon, Pokémon Ultra Sun, Pokémon Ultra Moon.
Pokémon moved to Pokémon Sun/Moon/Ultra Sun/Ultra Moon will not be able to go back to their original game (but you can still put them in the Pokémon Bank).
Third step : 3DS to Nintendo Switch
To bring your Pokémons from 3DS to Nintendo Switch, you'll need to put all your Pokémons to PokéBank.
Then using the app "Pokémon Home" available on smartphones and Nintendo Switch you'll be able to import Pokémons from Pokémon bank.
Pokémon moved from 3DS could be moved to Pokémon Sword and Shield, but can't go back to their original versions.
This part will be updated when further details revealed
Side note : Pokémon let's GO (Pikachu/Eevee)
Pokémons from Pokémon let's GO will be transferable to Pokémon Home (one-way)
This part will be updated when further details revealed
Side note : Pokémon GO
Pokémons from Pokémon GO are transferable to Pokémon let's go (one-way) Pokémons from Pokémon GO will be transferable to Pokémon Home (one-way)
This part will be updated when further details revealed
Side note : 3DS Virtual Console games
The Pokémon Bank is also compatible with virtual console versions of Pokémon Red/Blue/Yellow and Green (only available in japan) released in 2016 and with Pokémon Sivler/Gold/Crystal released in 2017.
As for Pokémon Sun/Moon/Ultra Sun/Ultra Moon Pokémons can only be transfered to Pokémon Bank but they can't go back to their original game (Mew and Glitch Pokémon are not eligible for transfer from virtual console).
For further information check out this article from Nintendo on how Pokémon Bank works with all compatible Pokémon games.
Side note : Pokémon Colosseum / Pokémon XD (NGC)
Pokémon obtained from Colosseum and XD (Nintendo Gamecube) can be traded to Gameboy Advance versions using Gamecube to GBA cable.
Pokémons need to be healed from darkness in order to be traded
Side note : Time is running out
Nintendo 3DS is near (if not already reached) to its end of life, this means that Nintendo eshop will close sooner or later, this will prevent you from downloading : Pokémon Bank and Poké Transporter.
Why such a long process ?
Because Nintendo thinks the process in a generation to generation transfer instead of an 'any generation to any generation' transfer. Moreover, not all generation are compatible between them in term of available Pokémons. Today, things are going much simpler thanks to Pokémon Bank and Pokémon Home.
What's the shortest path ?
- Keep your GBA games.
- Get a Nintendo DS (not DSi as it lacks advance slot)
- Get Pokémon Diamond (or Pearl) (or Platinum) (or HG) (or SS)
- Finish the Pokémon Diamond (or the one you got at 3.) on the DS
- Transfer Pokémon from GBA to Diamond
- Get Pokémon Black (or White) (or W2) (or B2)
- Finish the game you get at 6.
- Transfer your Pokémon from Diamond (or the one you got at 3.) to Pokémon Black (or the one you get at 6.)
- Get a 3DS
- Get Pokémon X (or Y) (or Omega Ruby) (or Alpha Saphyr) (or Sun) (or Moon) (or Ultra Sun) (or Ultra Moon
- Get Pokémon Bank
- Get Poké Transporter
- Transfer Pokémon using Poké Transporter from Pokémon Black (or the one you got at 6.)
- Use Pokémon Bank to transfer Pokémon to Pokémon X (or the one you get at 10.)
- Get a Nintendo Switch
- Get Pokémon Sword (or Shield)
- Use Pokémon Home to transfer Pokémon from Pokémon Bank to the game you got at 16.
Why would I need a Nintendo DS, Nintendo 3DS can read Nintendo DS games ?
Indeed Nintendo 3DS can read Nintendo DS games, but Nintendo 3DS is not compatible with Gameboy Advance games. Only Nintendo DS (not DSi as it lacks advance slot) is compatible with GBA games.
Feel free to add precisions in comments I'll will update the post