Wall jets are important for a wide variety of engineering applications, including ventilation of confined spaces and cooling and drying processes. Although a lot of experimental studies have been devoted to wall jets, many of these have focused on laminar or turbulent wall jets. There is a lack of experimental data on transitional wall jets, especially transitional wall jets released into a confined space or enclosure. This paper presents flow visualizations and high-resolution Particle Image Velocimetry measurements of isothermal transitional plane wall jets injected through a rectangular slot in a confined space. As opposed to many previous studies, not only the wall jet region but also the recirculation region in the remainder of the enclosure is analyzed. The data and analysis in this paper provide new insights into the behavior of transitional plane wall jets in a confined space and will be useful for the validation of numerical simulations of this type of jets.