The Wonder Bar was a drinking establishment located on Starbase 12. In 2267, when the USS Enterprise put in for shore leave at the starbase, James T. Kirk visited the Wonder Bar with Maria Kellogg, Leonard McCoy, Uhura, and Spock. While there, they observed a scruffy-looking spice smuggler arguing with a pair of brown-uniformed pilots from a migrant fleet over a girl, who left with a tall, curly-haired man dressed like a space-tramp.

A few days later, Lieutenants Uhura and Hikaru Sulu were returning to the Enterprise from the Wonder Bar when they discovered two Klingons attempting to kill Trae. (TOS novel: Ishmael)

Since neither Star Wars nor Battlestar Galactica take place in the 23rd century, it is possible that the Wonder Bar is interdimensional in nature, not unlike The Captain's Table. Alternatively, they may have been brought there by the time travelling Doctor.