Version 3.1.0 (Splatoon 2)
- Main article: Octo Expansion
Version 3.1.0 added support for the Octo Expansion paid downloadable content.
Twelve new gear items were added. All players can see the items in-game, but only players who purchase the Octo Expansion are able to obtain the items for themselves.
Players can select an Octoling as their character for online battles after clearing the Octo Expansion's main story. All players can see Octolings in-game, but only players who purchase the Octo Expansion are able to unlock Octolings for themselves.
The Octo Shot Replica was added and can be used in multiplayer after beating the main story of the Octo Expansion.
Specifications for some of the main weapons have been changed.
|Dark Tetra Dualies||
| Undercover Brella
Undercover Sorella Brella
Hero Blaster Replica
Specifications for points required for some special weapons have been changed.
|.52 Gal||▲ 180 → 170|
|Krak-On Splat Roller||▲ 180 → 170|
|Enperry Splat Dualies||▼ 180 → 190|
|Dapple Dualies Nouveau||▼ 170 → 180|
- Fixed an issue causing shots from a Sloshing Machine or Sloshing Machine Neo to appear to cover stage obstacles with the opponent's ink color when they hit it directly after being fired from a certain angle.
- Fixed an issue causing opponents standing behind the launched umbrella portion of a Splat Brella or Sorella Brella to be difficult to see under the effects of Thermal Ink, a Sting Ray, or Haunt.
- Fixed an issue allowing players to dodge roll through the launched umbrella portion of a brella when approaching from a specific angle.
- Fixed an issue causing players Super Jumping to an ally who had entered an Inkrail after using an Inkjet to Super Jump to the beginning of the Inkrail.
- Fixed an issue causing missiles fired from a Tenta Missiles special to explode if they touched an opponent's Splash Wall or brella immediately after being launched.
- Fixed an issue causing the Super Jump sound effect to be delayed when performing a Super Jump while attacking with certain weapons with multiple Quick Super Jump gear abilities equipped.
- Fixed an issue in Starfish Mainstage preventing bombs thrown onto the sloped walkways on the sides of the stage from being inked when hit.
- Fixed an issue in Humpback Pump Track causing bombs and players to clip into stage features in the middle of the stage.
- Fixed an issue in Sturgeon Shipyard causing players Super Jumping to an ally standing on the edge of the area covered by the drawbridge to fall off the stage depending on the timing of their jump.
- Fixed an issue in Manta Maria causing players to be treated as if they'd fallen off-screen after performing a dodge roll on top of certain walls.
- Fixed an issue in Walleye Warehouse causing the aiming reticle to mistakenly indicate that a shot would hit when aiming at an opponent in squid form with a charger while they are near a spawn point, concealed by a stage feature, and in a higher position than you.
- Fixed an issue in Piranha Pit causing players moving across certain sloped surfaces to suffer a slight drag on their movement.
- Fixed an issue in Piranha Pit causing bombs thrown or brellas launched onto certain surfaces to disappear.
- Fixed an issue in Piranha Pit during modes other than Rainmaker, allowing players in the lower portion of the stage’s outer areas to clip into stage features.
- Reduced the space between certain crates and stage terrain in Piranha Pit during Turf War, Splat Zones, and Clam Blitz matches.
- Fixed an issue in Piranha Pit during Tower Control matches causing Splash Walls that bounce off the tower when thrown and then land on a conveyor belt to continue moving as if on the tower.
- Fixed an issue in Camp Triggerfish allowing players to jump over areas they were not intended to.
- Fixed an issue in Camp Triggerfish causing players to mistakenly encounter an impassable barrier when climbing certain walls in squid form.
- Fixed an issue in Camp Triggerfish allowing players in squid form to enter into the lower portion of handrails that certain weapon fire will not pass through.
- Fixed an issue preventing shots that move at high speed, such as a fully-charged charger shot from dealing damage after hitting their target directly.
- Fixed an issue causing Power Eggs picked up after Wave 3 ends, but prior to returning to the ship to not be added to the Power Egg count of the player who picked them up, even though they were accounted for in the team's total Power Egg count.
- Fixed an issue causing a single player to be carrying two Golden Eggs at the same time when multiple players pick up multiple Golden Eggs simultaneously.
- Fixed an issue in Marooner's Bay rarely causing players to clip into the ship.
- Fixed an issue when fighting the boss of Slimeskin Garrison with a weapon other than the Hero Charger causing unintended gibs to appear when defeating enemies.
- Fixed an issue causing the game to shut down when using an amiibo to change equipment on the Equip screen.
- Fixed an issue in Ranked Battle causing weapons not to glow at the start of matches after losing a match while playing with less than a full team due to issues like connection errors.
- Fixed an issue occurring in certain stages when taking pictures with an amiibo causing the player's character to float above the ground.
- Fixed an issue in The Reef when taking pictures with the Inkling Squid amiibo causing the player character not to be looking directly at the amiibo.
- Fixed an issue in Squid Beatz 2 causing the position of the green button prompt to appear slightly lower than intended when a green "press any button" prompt and a pink "press left and right at the same time" prompt occurred simultaneously.