A recreation officer was a title given to an officer aboard a starship who supervised the ship's recreation facilities.
Recreation officers managed a ship's recreation decks, recreation rooms, observation decks, gymnasiums and holodecks. They provided various games, sports, books to read, and other forms of entertainment to off-duty crew-members, and organized mass briefings, social functions and memorial services. They also played host to visitors, and provided facilities and foods appropriate to their biological and cultural requirements.
- As 23rd century holographic projections have been seen in the rec room in the TAS episode: "The Practical Joker", and recreation officer Harb Tanzer managed such projections, it seems reasonable to assume that 24th century holodecks also fall under the purview of recreation officers of that era.
In Starfleet, Recreation was a sub-division of the medical division, and recreation officers reported directly to the chief medical officer. A medical officer could prescribe recreation to those they felt needed a break. In turn, a recreation officer could report on crew morale, battle-readiness and physical and mental health. Recreation was usually a small department, but considered quite important to maintain and boost morale. The head of the recreation department was called the chief of recreation, or recreation chief. (TOS - Rihannsu novel: My Enemy, My Ally; TOS novels: Mission to Horatius, The Wounded Sky, Spock's World, Rules of Engagement)