Abstract The feasibility of using flexible polymer microtubes as photocatalyst supports was investigated by using PFA tubes of various inner diameters (i.d.). Catalyst immobilisation was performed by loading a prepared TiO2 suspension into the tubes, which were then subjected to a quick thermal treatment at 285°C. The presence of the catalyst on the inner walls of the tubes was confirmed by SEM-EDS analysis, and the thicknesses of the resulting catalytic layers were evaluated by SEM for different catalyst precursor concentrations. The performances of the reactors were investigated by the photocatalytic degradation of phenol. The apparent reaction rates observed on these reactors were found to be one order of magnitude larger than found in a small batch vessel operating with suspended slurry. The effects of the number of catalytic coatings, the concentration of the catalyst precursor suspension, the reactor inner diameter and the initial pH of the solutions on the performance of the reactor were investigated.