The largest supported capacity of a microSDXC card for Nintendo Switch is 2 TB.
Nintendo Switch supports microSD, microSDHC, and microSDXC memory cards for expanding storage. The system’s official specifications list support for microSDXC cards with capacities up to 2 TB. This matters because many Switch games are distributed digitally or require substantial downloadable updates, while the console’s internal storage is limited.
A 2 TB card is the maximum supported capacity, not the amount of storage included with the console. The original Switch and Switch Lite contain 32 GB of internal storage, while the Switch OLED model contains 64 GB. Some of that built-in space is used by system software, so the usable capacity is lower.
microSDXC cards generally require the console to perform a system update before use, and downloaded games remain associated with the Nintendo Account that obtained them. Memory cards can be moved between consoles only under conditions involving the software and account, so a card is not a simple unrestricted transfer of installed games.