"Raiders" is a collective term that refers to a number of different groups of pirates and criminals that prey on the shipping lanes (mostly on the frontiers between non-aligned worlds, border worlds and colonies), mostly on merchant vessels and passenger liners. They often have ties to smugglers, arms dealers, hijackers, and sometimes even have unofficial support from local governments as a de-facto privateer force.
- One faction of Raiders near Babylon 5 maintained a secret deal with the Narn Regime in 2258 to purchase weapons and equipment. The Narn even supplied a short-range depot hidden in an asteroid field that came complete with a Narn operative (whose role was not only to help them set up the weapons but to ensure they were not resold). This outpost and the Narn supply of heavy weapons was disrupted through the actions of Cmdr. Jeffrey Sinclair, commander of Babylon 5 at the time.
- This same faction (or possibly a separate one) was still able to persist as an ongoing threat to interstellar security throughout 2258. However, their gradual rise in activity near the League worlds was completely disrupted following the loss of their entire fighter complement in the First Battle of Babylon 5 and the subsequent destruction by the Shadows of their battlewagon.
- In 2261, several groups taking advantage of the general chaos and new-found abundance of military hardware in the aftermath of the Shadow War began hitting supply ships, though at least some of these attacks were found to have been carried out by Drakh forces.  One particular group was stopped when an apparently lightly defended shipment of Quantium 40 turned out to be a "mouse trap" set by the Army of Light.
- In 2262 One group of raiders that had been harassing the Enphili was found to have been secretly supported by the Drazi Freehold for at least ten standard years. These Raiders, spurred by the protection offered by their secret ties to the Drazi, were particularly brutal to the Enphili, keeping their entire planet virtually hostage. 
- Even with the establishment of the Interstellar Alliance, Raider activity was still enough of a problem that one group was able to disable and nearly destroy the Ranger ship Enfali in 2265.
- They are known to operate in Grid 471 by 18. This is a concern when the Asimov was disabled in the area.