The Ilidarians were a spacefaring species native to Ilidaria in the Delta Quadrant.
When USS Voyager was trapped within the event horizon of a type 4 quantum singularity in 2371, Neelix suggested that they request help from Ilidaria. He noted that the Ilidarians had sophisticated technology and were "quite friendly, most of the time." (VOY: "Parallax")
Later that year, Commander Chakotay and Lieutenant Tuvok conducted a trade mission with the Ilidarians. On the way back, their shuttlecraft was attacked by the Komar in a dark matter nebula. (VOY: "Cathexis")