A couple years ago I wrote up this little post about how to transfer Pokémon between generations.
Unfortunately, since the Generation VI games, moving any Pokémon from an old generation requires an internet service provided by Pokémon, and internet services have a habit of becoming unavailable or discontinued.
Next month the Nintendo 3DS eShop will be shutting down, which means that it will no longer be possible to download some of the software to perform these transfers. After that, it's anyone's guess as to how long the servers stay online.
I wanted to get in one of these maximum-generation transfers before that date, so I bred a few Eeevees in Pokèmon Emerald, with the goal of bringing them into Pokémon Home, and then hopefully soon I can bring them into the Generation IX games (Scarlet/Violet) once they gain Home compatibility.
Generation III to Generation IV
To migrate Pokémon from Generation III (Ruby/Sapphire/Emerald/Fire Red/Leaf Green) to Generation IV (Diamond/Pearl/Platinum/Heart Gold/Soul Silver), you need a Nintendo DS. The original. Not even a DSi will do. You need the original hardware that has both a DS game cartridge slot as well as a GameBoy Advance game cartridge slot.
Once you've advanced in your Generation IV game to a point where you've unlocked Pal Park, you can migrate Pokémon from the Generation III game. Simply insert both games into the Nintendo DS at the same time, and select Migrate from the game's startup menu:
After this you'll be asked to pick exactly 6 Pokémon to migrate - no more and no less.
Once you've done that, head over to Pal Park where you'll have to join a Catching Show. This basically entails running around the terrain where your Pokémon will spawn, and throwing special Park Balls at them, which by the way have a 100% catch rate. Your recaptured Pokémon will retain the balls they were originally caught in, as well as their original OT (Original Trainer), nickname, etc.
After catching all 6 Pokémon, they get placed in your PC boxes, and now we can bring them to Generation V.
Generation IV to Generation V
To migrate Pokémon from Generation IV (Diamond/Pearl/Platinum/Heart Gold/Soul Silver) to Generation V (Black/White/Black 2/White 2), you need two Nintendo DS/DSi/2DS/3DS devices. One of them plays the Generation V game, the other opens DS Download Play with the Generation IV game cartridge inserted.
To start the process, you need to make your way to the Poké Transfer Lab on Unova Route 15. There you can start a DS Download Play server, and that's about all you do on this device.
Back on the second device with the Generation IV game loaded, select up to 6 Pokémon to transfer at once.
Now you're faced with one of the most annoying minigames that Pokémon has to offer - you're basically given a Poké Ball catapult and have to launch slow-moving balls at your Pokémon as they run around a field and hide in bushes.
Once you (eventually) complete that, the transferred Pokémon are placed in your PC boxes.
Generation V to Pokémon Bank
This is where things get tricky and annoying with the Nintendo eShop closure looming.
To migrate Pokémon from Generation V (Black/White/Black 2/White 2), to Generation VI or newer, you need to transfer them to Pokémon Bank.
This requires that you have the Pokémon Bank application. For the moment it also requires that you have an active Pokémon Bank subscription. And lastly, it requires that you have downloaded the Poké Transporter application, which you can only do through the Pokémon Bank application.
Assuming you have all that, open your Generation V game and make sure that PC Box 1 contains only the Pokémon that you wish to transfer to Pokémon Bank. Then, open Poké Transporter and transport your Pokémon into the cloud.
Once they arrive in Pokémon Bank they will be in the Transport Box. I don't know if the Home transfer can see this, so I moved them out into a regular Pokémon Bank Box anyway just to be sure.
Pokémon Bank to Pokémon Home
To migrate Pokémon from Pokémon Bank to Pokémon Home, you need an active Pokémon Home Premium subscription, and either Pokémon Home for Nintendo Switch, or Pokémon Home for iOS or for Android. You don't even need the 2DS/3DS anymore, if both Bank and Home are tied to the same Nintendo Network ID.
On the Nintendo Switch version, there is a migration button on the main screen after the application logs in. On the iOS and Android versions, there is a Move Pokémon button under Options > Account.
Both Pokémon Bank and Pokémon Home have very good inbuilt documentation for this. Press the buttons and follow the instructions and you can't really go wrong.
Nothing that Pokémon or Nintendo could really do at this point would take away the ability to move Pokémon between Generations III and IV, IV and V, or for that matter to trade Pokémon between Generations I and II. All of that happens offline between two devices.
Making Pokémon transfers require cloud services with the launch of Pokémon X and Y in 2013 always made me a little bit uneasy because cloud services are not forever. Although people say that the internet is forever, services die, links rot, and things do actually become unavailable or get forgotten.
With the closure of the eShop next month, only people who are prepared and had the opportunity to be prepared will be able to transfer Pokémon from Generation V, VI, or VII to newer games. New players who want to revisit old games may never be able to do this. Even for those of us who will still be able to perform these migrations are at the mercy of service availability and maintenance.
I do miss technology that used local area networks and could work without an internet connection, and I wish they would bring that back.
Not everything needs to be a cloud service.