Currently, almost all polymer optical materials are derived from fossil resources with known consequences for the environment. In this work, a processing route to obtain cellulose-based biopolymer optical fibers is presented. For this purpose, the optical properties such as the transmission and the refractive index dispersion of regenerated cellulose, cellulose diacetate, cellulose acetate propionate, and cellulose acetate butyrate were determined from planar films. Cellulose fibers were produced using a simple wet-spinning setup. They were examined pure and also coated with the cellulose derivatives to obtain core–cladding-structured optical fibers. The cellulose-based optical fibers exhibit minimum attenuations between 56 and 82 dB m–1 at around 860 nm. The ultimate transmission loss limit of the cellulose-based optical fibers was simulated to characterize the attenuation progression. By reducing extrinsic losses, cellulose-based biopolymer optical fibers could attain theoretical attenuation minima of 84.6 × 10–3 dB m–1 (507 nm), 320 × 10–3 dB m–1 (674 nm), and 745.2 × 10–3 dB m–1 (837 nm) and might substitute fossil-based polymer optical fibers in the future.