Most Operators in Arknights have skills; strong, triggerable abilities that can aid them or other Operators offensively or defensively by enhancing their stats, modifying their functionality, or adding new functions altogether.
- 3★ Operators only have a single skill that is available initially.
- 4★ and 5★ Operators have two skills; the first is available initially and the second is available once they are promoted to Elite 1.
- 6★ Operators have three skills; the first is available initially, the second is available once they are promoted to Elite 1, and the third is available once they are promoted to Elite 2.
Operators with multiple skills can only choose one of them to be use at a given time, which is done from the Operator or squad menu.
Generally the first skill is a generic skill shared across all Operators of the same class and/or archetype, while the second and third skills are unique to each Operator and often act as core to the Operator's playstyle.
All skills cost SP (Skill Point) to use, which are generated in three different ways:
- Automatic Recovery: 1 SP is generated every second.
- Offensive Recovery: 1 SP is generated each time the Operator attacks (including healing for Medics).
- Defensive Recovery: 1 SP is generated each time the Operator is hit by attacks, both melee and ranged (including Arts); if the incoming attack is dodged, no SP will be added.
Most skills start out with a number of SP already generated when the Operator is deployed, which is referred to as "initial SP" and denoted by white arrow:
Skills are activated in two different ways, both of which requires valid target(s) to be present within the skill's range if it requires one:
- Auto Trigger skills are activated as soon as the Operator have enough SP.
- Manual Trigger skills are activated on the player's command, which can only be done when the Operator have enough SP.
Certain Operators have passive skills which are active at all times and do not require the player's input to function, although some are context-sensitive.
Most skills last for a short duration, but some skills last for an unlimited duration (actually for a very long duration; see Trivia for details).
Skills can be upgraded by leveling them from the Skill Upgrade menu on each Operator's Character Details page. Skills can be upgraded through 7 levels, and all of the Operator's skills (in case they have more than one skill) will be upgraded at the same time.
Upgrading skills require the following:
|Few T1 upgrade materials|
|Few T2 upgrade materials|
|Few T3 upgrade materials||Promoted to Elite 1|
|Some/few T1 upgrade materials|
|Some/few T2 upgrade materials|
|Promoted to Elite 1|
|Some/few T3 upgrade materials|
|Some T1 upgrade materials|
|Some T2 upgrade materials|
|Promoted to Elite 1|
|Some T3 upgrade materials|
Once the Operator's skills are at Level 7, they can be further improved to three additional levels through the Mastery, also known as Specialization, training function. Only 4★ Operators and above that has been promoted to Elite 2 can undergo Mastery training.
Mastery training is done at the Training Room of the RIIC. The process takes time to complete (which can be accelerated by assigning certain Operators as trainers), and unlike skill upgrades, are done individually for each skill.
Mastery trainings require the following:
|Some/few T4 and T3 upgrade materials||8 hours||Level 1 Training Room|
|Some T4 upgrade materials||16 hours||Level 2 Training Room|
|Some/few T5 and T4 upgrade materials||24 hours||Level 3 Training Room|
|Some T4 and T3 upgrade materials||8 hours||Level 1 Training Room|
|Many/some T4 upgrade materials||16 hours||Level 2 Training Room|
|Some T5 and T4 upgrade materials||24 hours||Level 3 Training Room|
- Mastery training is very resource- and time-consuming, especially for 6★ Operators. Thus it is important to know how significant the boost to the skill will be and whether or not it is worth farming the materials for.
- Skills with "unlimited" duration actually last for up to 30 minutes; however, the skill will almost never be deactivated during any operation as it greatly outlasts the average operation time.
- Even though 1★ and 2★ operators have voice lines for skill activation, they can never be heard during operations, due to their lack of skills.