The optics of the 160‐keV deuterium neutral beam injection for the Joint European Torus–plug‐in neutral injector (JET‐PINI) have been studied in a single beamlet, using the test stand ligne d’etudes d’optiques (LEO). The beamlet optical features, that is perveance‐divergence relationships, beam profiles, and steering angle by aperture offset, have been measured. Computations have been compared with the experimental results obtained both in this monobeamlet experiment and in the multibeamlet system of the 160‐keV PINI injector.