For years, Nintendo was the last holdout for free online multiplayer on home game consoles. Tomorrow, that changes: on Sept. 18th, Nintendo is launching its own paid online service called Nintendo Switch Online. It costs $3.99 a month or $19.99 a year -- and will be required for Switch owners who want to play multiplayer games over the internet. In other words, the service is effectively putting parts of major titles like Splatoon 2 and Mario Kart 8 behind a paywall. 

But if you were wondering about one of the most popular games in the world, Fortnite, don't fret. You'll still be able to hop into the battle royale even if you don't have a Nintendo Online account.

The online service will also launch with numerous Nintendo Entertainment System titles, including Mario Bros., Excitebike, Dr. Mario, Balloon Fight and other NES classics. As mentioned earlier in the year, several of these titles will include new online functionality. And beyond the launch lineup, Nintendo promised a "growing library of online games."

The Nintendo Switch app will remain the primary means of communicating with other players during online play. Nintendo also teased special offers for subscribers, including a pair of wireless Switch controllers that will look and feel like the classic NES gamepad, and can dock with the Switch to charge.

Other special offers are coming, but Nintendo would only say it'll have "more to announce in the future."

An individual annual subscription costs $19.99 -- but you have multiple accounts you can save a bit more with a family memberships, available $34.99.

The online service has been long subject to speculation from fans wondering how it'll stack up to Sony's PlayStation Network and Microsoft's Xbox Live. Both of those are required to play most games online and offer free monthly games, but cost $59.99 for yearly subscriptions.

The Switch will be the first Nintendo console to require a paid subscription to access online multiplayer, and its first console to offer cloud saves, which Nintendo says will backup up your games to the cloud automatically (though there are several exceptions to that). Switch owners will be able to sign up for a seven-day free trial for the service before its limits go into full effect.

Nintendo's announcement had previously been planned for last week, before being delayed due to an earthquake in Hokkaido, Japan.

You can watch the Nintendo Switch Online segment of the presentation below.