Rectangular jets exhibit axis-switching behavior which results in enhanced flow entrainment compared to round jets. This feature allows for their potential industrial use as passive flow controllers in mixing applications. However, rectangular jets have received limited attention compared to round jets. To operate rectangular jets optimally, a better understanding on the underlying phenomena influencing the axis-switching of the jet is required. In this paper, Direct Numerical Simulations of rectangular jets are performed at different injection velocities using the Local Front Reconstruction Method (LFRM) to track the liquid–gas interface. The simulations are validated using experiments in a similar range of Weber and Reynolds numbers. The obtained results showed that LFRM can accurately capture the jet oscillations, break-up lengths and droplet sizes observed experimentally. Additionally, a fully developed velocity profile at the nozzle outlet enhances the jet stability resulting in larger break-up length values compared to a uniform velocity profile.