We investigate the experimental response of additively manufactured tensegrity prisms under compression loading and different states of internal prestress. Physical models of tensegrity prisms are additively manufactured through an electron beam melting facility. Spectra strings are applied to the 3D printed models through a post-tensioning approach, which endows the structure with the desired prestress. Experimental tests highlight that the examined structures exhibit strongly nonlinear mechanical response under compression, which appears to be useful for the construction of a new class of nonlinear mechanical metamaterials featuring solitary wave dynamics to be controlled by internal and external prestress.