Splatoon 3 is introducing 'ghosts', 3D holograms for your online friends that will appear in the lobby. You can see what they're up to while they have captions like, "I created a room for an Anarchy Battle (Open!)" which you can then join, easily accessing battles.
"Drop in on friends in the midst of battle and play alongside them," the Nintendo Direct said. "You can also join them to start a battle on the same team. You'll be able to see what your friends are up to [and] it appears that you can call out to friends in the lobby and invite them for battles."
In the stream, one friend says, "I'm starting a Regular Battle", which the player then interacts with. When entering the dialogue menu, you can see that it's a Turf War on Undertow Spillway and Hagglefish Market. There's an option to drop in alongside a player count of one out of eight. You can also see how new the posting is. In the example mentioned, there's a 'one minute ago' timer on the top right of the box.
However, when dropping in, a warning displays, "You might be put on a different team than this player." So while you can interact with these 3D hologram ghosts in the lobby to join your friends' games, you might end up fighting against them rather than with them. Regardless, it should make playing together a little easier.
Once you join, you'll be put into a new menu where you can ready up. Here is where you'll be "waiting for players to join" with the stage and rules laid out on the left. Once you've readied up, you'll be thrown into the game. And in the test range, you'll even be able to see the ghosts of your friends as they beat up dummies and splatter goo.
Splatoon 3 launches on September 9, 2022, for Nintendo Switch, so if you fancy trying out the newest entry in Nintendo's hit multiplayer series, you can pre-order right now.