Inkopolis Plaza is the hub world of Splatoon. From here, players can access various types of modes andshops as well as interact with other player Inklings they've battled with recently. It is the heart of Inkopolis, and the one of the only parts of the city of Inkopolis. 

Inkopolis Tower - Inklings can compete in online multiplayer battle modes.

Battle Lobby - Inklings can choose a mode category to play.

Octo Valley manhole - Inklings can play Octo Valley singleplayer missions.

Arcade Machine - Inklings can play the Squid Jump, Squid Racer, Squidball, and Squid Beatz mini-games.

Battle Dojo building (second floor) - Inklings can access the 1v1 local multiplayer Battle Dojo mode.

Spyke alley - Inklings can talk to Spyke, who can upgrade gear for Super Sea Snails or Cash.

Amiibo area - Inklings can play amiibo challenges with the Splatoon amiibo figures.

Miiverse mailbox - Inklings can post to the Splatoon Miiverse community.

Inkopolis News studio (second floor) - Inklings can see the Squid Sisters' studio.

Pledge Box (during Splatfest) - Inklings can choose Splatfest team.

Booyah Base - A local mall comprised of a variety of gear shops.

Ammo Knights - Weapon shop run by Sheldon.

Cooler Heads - Headgear shop run by Annie and Moe.

Jelly Fresh - Clothing shop run by Jelonzo.

Shrimp Kicks - Shoe shop run by Crusty Sean.