ABSTRACT: Microreactors enhance biodiesel yields due to their more efficient mixing mechanisms and faster mass transfer rates than conventional batch processes. In this investigation, microreactors with different designs and geometries (four T-shaped with different lengths, one Y-shaped, and one Tesla-shaped) have been successfully fabricated at Fab Lab Bahrain using a high-resolution CO2 laser cutting machine. Then, the performances of these microreactors for the continuous production of biodiesel were tested and compared. The transesterification of the 9:1 molar ratio of methanol to oil was operated at a temperature of 60◦C, with a 1.0 wt% NaOH catalyst. The performance of each microreactor for biodiesel synthesis was experimentally studied. The highest biodiesel yield was found to be 97.9%, with the Tesla-shaped microreactor at a residence time of only 4.85s, while the T- and Yshaped microreactors give the highest percentage yield of 93.3% and 94.3%, respectively, with a residence time of 3.28s each. Online monitoring of the microchannel using optical imaging showed a mixing percentage of 97.6%, 97.87%, and 99.52% with T-, Y-, and Tesla- shaped microreactors, respectively, which consolidates the mixing effect’s on developing the percentage yield of biodiesel.