Pokémon FireRed and LeafGreen on Nintendo Switch do not support online play, but players can connect locally with up to four others through the Pokémon Wireless Club. The games also feature Union Rooms, where trainers can trade, battle or enjoy a minigame together. While the experience is limited to local connectivity, these options allow fans to interact and compete with friends, preserving much of the social gameplay that was central to the original Game Boy Advance releases.
Source: Nintendo.com and Pokemon.com
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