Mario Golf, the Game Boy Color classic, is available and ready to download off the North American and Japanese eShops. Originally released in 1999, Mario Golf was the sequel to the Nintendo 64 game of the same name. The game features six courses and 12 playable characters, as well as a few mini-games and new modes.
You can download the game through the eShop or by following this link and scanning a QR code with your 3DS. The game is on sale for $4.99 and there is no word on a release date in Europe and Australia.