Dual-slot mode

Dual-slot mode (Japanese: ダブルスロット Double-Slot) is a method of communication between a Nintendo DS game card and a Game Boy Advance game cartridge by inserting both into the same Nintendo DS system. However, due to the removal of the GBA slot, dual-slot mode is not available if the player is using a system from the Nintendo DSi family or Nintendo 3DS family.

Pal Park
In, Pal Park allows the player to transfer Pokémon from , using dual-slot mode for communication. Additionally, someone at Pal Park will give accessories to the player if there is a game cartridge in the DS.

The Pokémon are sent from the Generation III game to the Generation IV game, and cannot be sent back.

Dongle method
In, the dongle method changes the wild Pokémon that appear based on the game in the Game Boy Advance slot, via dual-slot mode. This method is compatible with any of the Generation III core series games:. The name "dongle method" is an unofficial name that comes from the fact that this method uses the Game Boy Advance game as a for the Nintendo DS game.

After obtaining the National Pokédex, if the player had an applicable GBA game of the same language inserted in the GBA slot when they opened the title screen, the dongle method allows specific wild Pokémon to appear depending on the GBA game. Wild encounters will not change if a GBA game is inserted or removed from the Nintendo DS system after the title screen. GBA games of different languages to the DS game will not affect wild encounters.

The wild Pokémon that can appear this way are mostly not in the Sinnoh Pokédex in Pokémon Diamond and Pearl. They are usually game-exclusive Pokémon to one of the Generation III games. They usually have an 8% chance of appearing, or 4% each if there are two different Pokémon that can appear this way in the same location due to the same game.

Pokémon Dream Radar has a similar feature that allows players to catch a Generation IV game mascot with its Hidden Ability in extensions unlocked by putting the Game Card of the corresponding game into the game card slot of the Nintendo 3DS system.

Event distributions
In the Generation IV core series games, some event distributions were done using a Slot 2 cartridge, which was inserted into the GBA slot to send data to the DS game card.

In Pokémon Dash
In Pokémon Dash, players can make custom cups based on the party in a Generation III core series game inserted in the GBA slot. sprites are used; patterns are retained, but  coloration is not depicted. s in the player's party are ignored.

The Japanese, European, and American versions of Pokémon Dash have no region checks, allowing the player use any language game (although only the first 5 characters of a Pokémon's name will be displayed in the Japanese version of Pokémon Dash). The Korean version only allows Japanese game cartridges to be used.

In Pokémon Mystery Dungeon: Red Rescue Team and Blue Rescue Team
In Pokémon Mystery Dungeon: Blue Rescue Team, dual-slot mode allows the game to communicate with Pokémon Mystery Dungeon: Red Rescue Team.

If the player has both games inserted into a compatible system, SOS Mail can be sent between the games, allowing for the rescue team in one game to save the team in the other cartridge's save file.

In Pokémon Mystery Dungeon: Blue Rescue Team, the player can use Receive Team while Red Rescue Team is in the Game Boy Advance slot. If used, the rescue team from Red Rescue Team becomes the boss of the Rescue Team Maze of Makuhita Dojo.