List of post-release content in Splatoon

"Callie: We've got some update information to share! Marie: What is it? What is it?!"

- Squid Sisters

"Every week or two, new free content will be introduced in #Splatoon, including weapons, stages and gear."

- Nintendo of America's official Twitter

Downloadable content, or DLC, is additional post-launch content released for Splatoon. Nintendo frequently releases new weapons, stages, modes, features, and gear. Usually, Nintendo announces the release date of upcoming content via their social media accounts. An Inkopolis News announcement introduces the new content when it is released. Interestingly, most additional content is already in Splatoon, waiting to be unlocked by Nintendo. There have been 11 new weapons, 4 new stages, 1 new mode category, and 2 new modes released thus far.

Confirmed DLC leaks
Some leaks for upcoming DLC have been confirmed.

Datamine DLC leak
NWPlayer123 datamined Splatoon and found files for upcoming DLC weapons, stages, and modes.

Prima Strategy Guide "Coming Soon" section
The Prima Strategy Guide for Splatoon includes a "Coming Soon" section which shows off weapon and stage DLC. There are also two images of Tower Control. All of the content has been released.

Weapons

 * Carbon Roller
 * Custom E-Liter 3K
 * E-Liter 3K Scope
 * Inkbrush
 * L-3 Nozzlenose
 * N-Zap '85
 * N-Zap '89
 * Rapid Blaster Deco
 * Splash-o-matic
 * E-Liter 3K Scope

Stages

 * Bluefin Depot
 * Kelp Dome
 * Camp Triggerfish
 * Port Mackerel

August Update Event
This August, a "huge matchmaking update" is expected. This will add a slew of new matchmaking features, including friend-based matchmaking. This will allow either 4 Wii U friends to team up against another group of 4 Wii U friends, or allow 8 Wii U friends to secure a lobby for themselves, where the group will be able to decide the stage and ruleset.

This update will also include new clothing (as stated by the direct) and much more.

Squid Girl DLC
Sometime in August, a Splatoon x Squid Girl crossover DLC is due. Revealed on Masahiro Anbe's official Twitter, the DLC is to feature costumes, from the manga/anime. Official art was also released with the tweet, and the following issue of Weekly Shōnen Champion also featured an ad to further confirm the crossover. No word has been made on the DLC leaving Japan.

Famitsu Squid Fashion Contest
In their May 20th issue, Famitsu offered a Splatoon costume design submission contest, with the winning entry being added to the game. The selected winner was The Festival Octopus Chef. The DLC will be added alongside the aforementioned Squid Girl DLC.

= Splatoon DLC for other games =

Super Smash Bros
Three Splatoon themed costumes were added to Super Smash Bros. for 3DS and Super Smash Bros. for Wii U on June 14th 2015, two days before Nintendo's E3 Digital Event was held on June 16th 2015.

On Friday June 5th 2015 Masahiro Sakurai, the creator and director of the Kirby and Super Smash Bros. series, officially announced on a Miiverse post that the DLC costumes would be released.

Those who preordered Splatoon at GameStop received a free code for these costumes, though they couldn't be obtained until the official release.

The Splatoon-themed DLC includes a full outfit for Mii Fighters and a Trophy of an Inkling.

= References =