Nintendo Switch Online is now available for purchase following the launch of the 6.00 system update and completed maintenance of the Nintendo eShop.
Originally scheduled to be available tonight after 8pm PT/11pm ET/4am BST, the Nintendo Switch Online service has gone live early and allows subscribers to access the previously free online play, Nintendo Entertainment System games, cloud saves, access to special offers like the NES-style controllers, and more.
Source: IGN.com Nintendo Switch Online is Live Now