Gear ability

Gear abilities, or simply abilities, are special attributes that are placed on wearable gear in and. They provide different effects depending on the ability present and their strength is based around the number of copies if they are stackable.

Primary abilities
Each piece of gear has a specific primary ability (also called main) which cannot be changed. In Splatoon, each piece of gear has a set primary ability which never varies. In Splatoon 2, some gear (namely, gear obtained through ) does not have a default primary ability and instead gets a random one generated from all the abilities available for that type of gear. In addition, all the starting gear and all the gear normally purchasable in shops regularly appears on the SplatNet 2 shop with different abilities than the normal ones.

By default, no gear in Splatoon or Splatoon 2 has a primary ability that matches the secondary ability favored by the brand that produces it. This is done to make acquiring gear with all 4 slots having the same ability (colloquially called "pure" gear) more difficult. However, SplatNet 2 gear is sometimes sold with a matching ability.

Primary-only abilities and mutual exclusivity
Some abilities can only appear as primary abilities. These abilities are also tied to a certain type of gear, preventing the user from having more than one ability exclusive to that gear type. For instance, if a player equips, they cannot also have because both abilities are only available in the main ability slot of headgear items. The groups of mutually exclusive abilities are as follows:

Because the has to be worn during Splatfest, every player will use the same clothing ability during Splatfest Battles.

Secondary abilities
All gear has 1-3 slots for secondary abilities (also called subs), which are weaker versions of the non-exclusive primary abilities. The effect is exactly three-tenths of a primary ability. The number of secondary abilities that can be present on a single piece of gear depends on the rarity (amount of stars) of the gear. The more stars there are, the more secondary abilities slots it comes with. Up to three secondary abilities can be present, meaning that the highest rarity is 3 stars. Secondary abilities are randomly chosen whenever a gear levels up, which happens when its bar is filled through battling. The points earned in matches go towards leveling it up. Higher rarity pieces of gear take more points to level up, even on the first slot, and each progressive slot on the same gear requires a larger amount of points.

Subs are rolled using random number generation (RNG).

There are 13 possible secondary abilities in Splatoon and 14 in Splatoon 2. Many brands make getting specific abilities either more common or less common. Brands that affect roll probability have a 5× chance of rolling a favored ability, and a 1/2× chance of rolling an unfavored ability.
 * In Splatoon, this means there is a 2/33 chance of rolling each of the 11 neutral abilities, a 1/33 chance of rolling the one unfavored ability, and a 10/33 chance of rolling the one favored ability. Brands that do not affect roll probability have a 1/13 chance of rolling each of the 13 abilities.
 * In Splatoon 2, this means there is a 2/35 chance of rolling each of the 12 neutral abilities, a 1/35 chance of rolling the one unfavored ability, and a 10/35 chance of rolling the one favored ability. Brands that do not affect roll probability have a 1/14 chance of rolling each of the 14 abilities.

Stacking
Stacked abilities have diminishing returns, meaning that each additional ability of the same type will have a slightly smaller effect than the previous. Diminishing returns make it impossible for players to gain over-powered stats, and make it undesirable to stack too much of the same ability. Diminishing returns may be more noticeable on some abilities than on others; abilities that have a small maximum effect or a small base stat being modified may feel especially ineffective to stack. For example, Swim Speed Up has a small maximum effect of 25%, so diminishing returns may seem severe relative to the other abilities. A player may not even perceive an improvement past a certain point, like after 3 main ability slots of Swim Speed Up.

This encourages players to wear a variety of different abilities, rather than focusing on one ability.

Splatoon
, who can be found in an alleyway in Inkopolis Plaza, will offer to re-roll secondary abilities or increase the gear's slots in exchange for Super Sea Snail or  Cash.

In Splatoon, some abilities are ineffective with certain Sub Weapons and Special Weapons, offering no improvements.
 * has no effect on non-throwable Sub Weapons: the, the , the , and the . It also provides no improvement for one throwable weapon, the.
 * offers no further improvements after it causes a weapon to reach its damage cap.
 * has no effect on the run speed while pushing a Roller.
 * has no effect on respawn time after drowning or falling, unless the player uses more than four secondary slots' worth of the ability.

Splatoon 2
, who can be found in Inkopolis Square (normally to the right of Deca Tower and in the middle of the square during Splatfests), has multiple abilities that affect gear items' secondary abilities: