Undoped and Ce3+-doped Lu3Al5O12 (LuAG) fibers were grown to evaluate their potential use in new particle physics experiments, such as dual-readout calorimeters. The choice of grown crystals was made to detect scintillation (doped LuAG) and Cherenkov radiation (undoped LuAG). Growth conditions for obtaining fibers with improved quality were found based on measurements of attenuation length of the fibers and cathodoluminescence measurements. The effect of annealing on attenuation length for LuAG and LuAG:Ce was also studied. In addition, we also evaluated a possibility to substitute LuAG by the cheaper mixed and (Lu,Y)3Al5O12 (LuYAG:Ce) fibers. •Undoped and Ce-doped LuAG fibers were grown by micro-pulling down technique.•Substitution of Lu3+ by Y3+ in (Lu1−xYx)3Al5O12 fibers improve Ce distribution.•Annealing of Ce-doped LuAG fibers improve the light propagation through the fibers.•Attenuation length over 1m can be achieved in LuAG:Ce after thermal annealing.