Starting today, active Nintendo Switch Online + Expansion Pack members can enjoy the Splatoon 2: Octo Expansion DLC on the Nintendo Switch system at no additional cost. It’s a great way to train up before the Splatoon 3 game launches for Nintendo Switch! Previously only available as a separate purchase, you now can dive into the large-scale, single-player expansion for Splatoon 2 with a paid Nintendo Switch Online + Expansion Pack membership!
In the Splatoon 2: Octo Expansion DLC you play as Agent 8, an Octoling who awakens without her memories on a dark subway platform. Navigate a mysterious underground test facility in this adventure that spans 80 missions packed with challenges you won’t find in the main game. Escape from these twisted depths, and you’ll be able to join multiplayer matches as your very own Octoling.
Source: Nintendo of America