Merging the responsibilities of ship-to-ship and personnel combat into a single department, the security & tactical department is responsible for the tactical readiness of the vessel and the security of the ship.
- Chief Security/Tactical Officer: The Chief Security Officer is called Chief of Security. Her/his duty is to ensure the safety of the ship and crew. Some take it as their personal duty to protect the Commanding Officer/Executive Officer on away teams. She/he is also responsible for people under arrest and the safety of guests, liked or not. S/he also is a department head and a member of the senior staff, responsible for all the crew members in her/his department and duty rosters. Security could be called the 24th century police force. The Chief of Security role can also be combined with the Chief Tactical Officer position.
- Assistant Chief Security/Tactical Officer: The Assistant Chief Security Officer is sometimes called Deputy of Security. S/he assists the Chief of Security in the daily work, in issues regarding Security and any administrative matters. If required, the Deputy must be able to take command of the Security department.
- Security Officer: There are several Security Officers aboard each vessel. They are assigned to their duties by the Chief of Security and his/her Deputy and mostly guard sensitive areas, protect people, patrol, and handle other threats to the Federation.
- Tactical Officer: The Tactical Officers are the vessels gunmen. They assist the Chief Tactical Officer by running and maintaining the numerous weapons systems aboard the ship/starbase, and analysis and tactical planning of current missions. Very often Tactical Officers are also trained in ground combat and small unit tactics.
- Security Investigations Officer: The Security Investigations Officer is an Enlisted Officer. S/He fulfills the role of a special investigator or detective when dealing with STARFLEET matters aboard ship or on a planet. Coordinates with the Chief Security Officer on all investigations as needed. The Security Investigations Officer reports to the Chief of Security.
- Brig Officer: The Brig Officer is a Security Officer who has chosen to specialize in a specific role. S/he guards the brig and its cells. But there are other duties associated with this post as well. S/he is responsible for any prisoner transport, and the questioning of prisoners. Often Brig Officers have a good knowledge of force-field technology and are experts in escaping such confinements.
- Master-at-Arms: The Master-at-Arms trains and supervises Security crewmen in departmental operations, repairs, and protocols; maintains duty assignments for all Security personnel; supervises weapons locker access and firearm deployment; and is qualified to temporarily act as Chief of Security if so ordered. The Master-at-Arms reports to the Chief of Security.