Mediates both influx and efflux of nucleosides across the membrane (equilibrative transporter). It is insensitive (EI) to low concentrations of the inhibitor nitrobenzylmercaptopurine riboside (NBMPR) and is sodium-independent. Specific for nucleosides, but may also transport hypoxanthine. May also play a role in the efflux of inosine and hypoxanthine from muscle cells during the net degradation of purine nucleotides that occurs during strenuous exercise and/or in the reuptake of these purines during the recovery process (By similarity). Resistant to dipyridamole and dilazep inhibition (anticancer chemotherapeutics drugs). Belongs to the SLC29A/ENT transporter (TC 2.A.57) family.