Starbase 39-Sierra serves as an important Federation starbase near the Romulan Neutral Zone since at least 2270. Over the past decades the starbase played a major role in Federation-Romulan relations and served as an intelligence base for Starfleet. The starbase was also the hub for rescue and relief efforts after the destruction of Romulus by the Hobus supernova in 2387, and the years that followed. As of 2409, it is commanded by Admiral T'nae, and the primary base of Starfleet operations close to Romulan space.
- Lieutenant Marrien ( Mk I-X weapons, Mk I-IX personal equipment and kits, and consumables)
- Xeno ( Mk I-X personal weapons)
- Commodity Broker Temev (Commodities)
- Commodities Broker
- Lieutenant Sarissa
- Ensign Bariet Jaran (Bridge Officers)
- Damar Kahn
- Ensign Jessiek (Ship Equipment Requisition)
- Ship Selections Officer (Starship Selection)
- Shuttle Information Officer (Shuttle Information)
- Ship and Shuttle Requisitions Officer (Ship and Shuttle Requisition)
- Lieutenant Commander Brocal
- Ambassador Vimok
- Lieutenant Synsa
- “Heading Out”: Admiral Quinn instructs the player to transport Damar Kahn from Starbase 114 in the Celes System to Starbase 39. From there, he intends to travel to the Hobus System aboard the U.S.S. Tucker. Once on Starbase 39, Damar provides the player with information about the Hobus supernova and the destruction of Romulus and Remus. He also informs the player that Sela has allies from the Delta Quadrant, but that he knows little about them.
- “Trade Deal”: Lt. Cmdr. Brocal invited Ambassadors Surah of the Deferi, the Rigelian Vimok and the Ferengi Ulish to Starbase 39 to help them coming to an agreement in their trade deal, which almost failed. When the talks were about to break down, the ambassadors refused to talk with Brocal, the situation became "way over [her] head". She is asking the player to help with the negotiations.
- “The Vault”: Commander Kyle DeSoto, who is located in Admiral T'nae's office, instructs the player that a shuttle must be used to approach the mysterious Romulan starbase in the Haakona System without drawing unwanted attention.
The station, as seen in the 23rd Century Sector Space
- In February 2011, Starbase 39 recieved a new Admiral's Office. This was the same layout with different decoration as the Earth Spacedock Admiral's Office that existed until the 1 Year Anniverary Update in February 2011.
- In February and March 2012, the station's lighting was revamped along with the addition of some new signs and improved background sounds. 
- Starbase 39-Sierra at Memory Alpha, the Star Trek Wiki.
- Starbase 39-Sierra at Memory Beta, the non-canon Star Trek Wiki.