Programmable photonic integrated circuits are emerging as an attractive platform for applications such as quantum information processing and artificial neural networks. However, current programmable circuits are limited in scalability by the lack of low-power and low-loss phase shifters in commercial foundries. Here, we demonstrate a compact phase shifter with low-power photonic microelectromechanical system (MEMS) actuation on a silicon photonics foundry platform (IMEC’s iSiPP50G). The device attains ( 2.9 π ± π ) phase shift at 1550 nm, with an insertion loss of ( 0.33 − 0.10 + 0.15 ) d B , a V π of ( 10.7 − 1.4 + 2.2 ) V , and an L π of ( 17.2 − 4.3 + 8.8 ) µ m . We also measured an actuation bandwidth f − 3 d B of 1.03 MHz in air. We believe that our demonstration of a low-loss and low-power photonic MEMS phase shifter implemented in silicon photonics foundry compatible technology lifts a main roadblock toward the scale-up of programmable photonic integrated circuits.