The high demand for polystyrene that is used in various commercial and household applications results in pollution of the marine environment and its accumulation in landfills. To tackle these global environmental issues, relentless efforts are required to recycle polystyrene waste into a new functional polymer, which can then be used for some applications such as flame retardancy and water repellency, by adding certain micro- and nanoinclusions. Hence, this research focuses on fabricating novel flame-retardant and superhydrophobic nanofibers through the electrospinning of a polymeric solution consisting of recycled expanded polystyrene (EPS), silicon dioxide (SiO2), and boric acid (BA). Several characterizations were done to study the surface chemistry, morphology, thermal decomposition, wettability, and fire retardancy of the prepared nanofibers. From this research, it can be concluded that the incorporation of both 10 wt% of SiO2 and BA inclusions in EPS gave the best results: a water contact angle of 156.98°, a total burning time of 25 s in the flammability test, and 83.75% weight loss of residue compared to 98.34% weight loss of pure EPS. The fabricated nanofibers could be used as protective layers in the electronics and packaging industries.