Do R4 Game Cards Work on Nintendo 3DS?

No, R4 game cards are not compatible with the Nintendo 3DS. R4 cards were designed for the original Nintendo DS and DS Lite; they use different technology and are not recognized by the 3DS hardware.

To play DS games on a 3DS, use the system’s built-in DSi Mode, which lets you access the DS library. For 3DS games, purchase them via the Nintendo eShop or physical retailers.