Star Trek: Eternity, often referred to as ST: Eternity or Eternity, is a Star Trek play-by-message-board role-play within the Federation Sim Fleet. It was created by Gabriel Logan, award winner of the 2002 Simming Prize for Literature. It was originally launched as a Guild Sim on August 30, 2010, earning recognitions for its creativity and originality. The game later moved into Spacefleet Online on August 3, 2012, and has become a full fledge member of the Federation Sim Fleet. It is currently being hosted by FSF Gabe and FSF Sail

Eternity has been labeled as being a "writing intensive experience," a game that practices quality over quantity; a facet that may frighten the casual player. It exploits darker themes not traditionally explored by other Star Trek novella, emphasizing situational attitudes and character context developed from cynical ambitions with undercurrents of spiritual motivations such as fate or destiny. Its story is over a decade in its conceptulization. Beginning after the events of Star Trek Countdown and carrying beyond the timeline proclaimed as being the PrimeTNG timeline. The story structure follows a Season/Epsiodic chrnologogy, with each Season representing an overarch story that begins and finds conclusion. 

Currently, Star Trek: Eternity is in Season 2. The role-play is slated to end after seven Seasons.