Starfleet Tactical are responsible for the protection of their posting against external attack, as well as the protection of all persons on their posting. They work closely with Security, but perform a different role.
A Field Tactician is specialised in using field tactics, such as during away missions on planets and moons. They are highly skilled in performing tactical operations.
Space Tacticians, similar to Field Tacticians, specialise in using tactics in non-atmospheric, low or zero gravity environments.
A Phaser Specialist has advanced training and knowledge of phasers, and is highly skilled in their ability to use one. They are frequently sharp shooters, capable of hitting a target at long range if needed.
An Explosives Specialist is a highly trained officer who is responsible for explosives, be that disarming them or placing them, e.g. breach charges.
Torpedo Specialists are responsible for maintaining torpedoes, as well as loading and operating torpedo tubes. They are also highly knowledgable in how to disarm them.
Armoury Officers are responsible for the armoury and its contents. They work very closely with Masters at Arms to make sure all weaponry is available should it be needed.
A Combat Analyst or Strategist is highly trained in the art of combat, and specialises in observing the enemy, determining the next move, and planning out tactical operations.
Flight Squadron Pilots are highly skilled pilots that operate fighters rather than shuttles.
A Field Tactics Instructor specialises in teaching officers field tactics, including survival, strategy, and combat.
A Hand-to-Hand Combat Instructor specialises in teaching officers different forms of hand-to-hand combat so they may better defend themselves in both unarmed and close-quarters scenarios.