Technically, Toby Fox didn't announce the exact release date, but he did state Undertale will come to Nintendo Switch in September 2018. He has also shared more details about a collector's edition players will be able to get before launch.
According to Toby Fox's Twitter announcement, the exact release date will be announced soon. The other part of his tweet was regarding Undertale's various edition for Nintendo Switch. Fans will be able to get the standard edition for $29,99 / €29,99 / ~£23 or collector's edition for $69 / €69 / ~£54.
While the prices seem to be rather ordinary at the first glance, I couldn't help but notice that the standard edition seems to be overpriced and collector's edition looks like great value for money. The collector's edition comes with two CDs containing about 100 songs from the official soundtrack, sheet music box with six song annotations by Toby Fox, a 24-page booklet illustrated by Tammie Change and a 14 karat gold plated brass locket doubling down as a music box.
That is a lot of stuff for hardcore fans of the game, but the standard edition is somewhat shifty. If you purchase it from the same store, it will cost three times more than it does on Steam and six times as much as it costs on GoG, since Undertale is on a 50 per cent sale there at the time of writing.
The only two incentives to get it, is because a player could desperately want to play it on the go, or if they desperately want a hard copy of the game. Or they could just buy it DRM-free on GoG and keep a hard copy of the game on a thumb drive.
To top it off, pretty much any computer ever can run the game. Its recommended specifications require 3GB RAM, a GPU with 512 MB RAM, a processor with 2Ghz and 200 MB disk space. Stick two wires from a 1960s TV into a potato and it will run the game. Many parts of Undertale are in black and white anyway.