At this time, those who have been playing the new remakes of Pokémon Brilliant Diamond and Shining Pearl are unable to transfer data between their game and their Pokémon Home account, though The Pokémon Company has plans to bring it to the game in the near future.
Right now, the service is compatible with other Nintendo games, like Pokémon: Let's Go, Pikachu! and Let's Go: Eevee!, Pokémon Sword and Shield, and Pokémon Bank (from the Nintendo 3DS).
While there isn't an exact release date just yet, the developers intend to release compatibility sometime in 2022 for all Brilliant Diamond and Shining Pearl players.
In August 2021, the developers confirmed that the compatibility was in the works with a tweet from the official Pokémon account.
"#PokemonLegendsArceus, #PokemonBrilliantDiamond, and #PokemonShiningPearl are all scheduled to be connected to #PokemonHOME in 2022!" the company tweeted. "More details will be announced in the future."
In the meantime, though, it is possible for players to transfer Pokémon between their Sword and Shield accounts to Brilliant Diamond and Shining Pearl — until Pokémon Home becomes available, that is.
Since then, there have not been new details released, though it'll likely happen sometime after Pokémon Legends: Arceus drops. The new game will veer widely from the traditional format the previous titles in the franchise have followed, making it an original experience for players.
At this time, though, there is no more information on when you'll be able to add the Pokémon you've captured in Brilliant Diamond and Shining Pearl to your Pokémon Home profile.