Sadly, Terraria won’t be making its way to the 3DS. Even though there’s significant interest on the part of creator Andrew Spinks, “the system unfortunately cannot run Terraria the way it needs to be ran.”
In an interview with RPS, Spinks said:
“I am wanting to code Terraria 2 in a more portable language so it can be released on multiple platforms at launch or close to launch. 3DS is something I was very interested in getting Terraria on but the system unfortunately cannot run Terraria the way it needs to be ran.”
Based on Spinks’ comments, perhaps Terraria 2 is something that could be more likely for the 3DS. If the game is being coded so that it’s more portable-friendly, then I don’t see why Nintendo’s handheld would be left out of the mix once again. But hey, I’m not a coder, nor am I making the game!