The 1995 game is the sequel to Secret of Mana, but it was only ever released on the Super Famicom in Japan. Unlike Secret of Mana, Seiken Densetsu 3 was never released on the Wii U's Virtual Console.
We’re still waiting to hear from Nintendo on when it plans to release Switch's Virtual Console. At Switch's launch, the company said fans can expect more information soon. We're already seeing some classic games pop up in the eShop; Hamster Corporation has released several Neo Geo titles.
In the meantime, fans of the Mana series can hold out hope they'll get to play SD3 in the future. Even if the game is only released in Japan, the Switch's region-free settings mean players from anywhere in the world would have their chance to wield the Mana Sword on Nintendo's new console.