Dislocations are line defects that play a central role in the mechanical deformation be- havior of crystalline solids [1]. Their activity is widely known to be pivotal in classical solids, controlling phenomena such as fracture and brittle-ductile transitions in metals and semiconductors. Much less is known [2], however, about the influence of dislocations on the properties of quantum crystals, which are solids where the quantum-mechanical zero- point kinetic energy is significant compared to the typical energy scale of the interatomic interactions [3]. Recent experimental studies on crystalline solid 4 $_{He}$, the propotypical quantum solid, indirectly indicate that dislocations are indeed involved in macroscopic phenomenona. The occurrence of apparent superfluidity [4, 5] and the observation of elastic stiffening [6–8], for instance, have been linked to the mobility of dislocations. However, in contrast to classical solids, for which an abundant body of experimental results exists, the lack of specific experimental data concerning the behavior of dislocations prevents a direct investigation of this relationship. In view of these difficulties, one needs to resort to theoretical approaches. In principle, a realistic picture of dislocations and their properties is possible using path- integral or variational Monte Carlo simulations. However, given that dislocation modeling requires a simultaneous treatment of different length scales [9], one associated with the core properties and the other associated with distances large compared to the atomic scale, the viability of these direct approaches remains a subject of debate [10–12]. In this Letter, adopting a methodology that incorporates both of the relevant scales, we obtain fundamental insight into the properties of dislocations in the archetypal quantum crystal: solid hcp 4 $_{He}$. We compute the intrinsic dislocation structure and mobility of four different dislocation types using the multiscale paradigm of the semi-discrete Peierls-Nabarro (PN) model [13–15]. It constitutes a hybrid continuum-atomistic approach that captures the long-range elastic fields as well as the lattice-discreteness effects associated with the dislocation core. All parameters in the model are determined using quantum-mechanical expectation values for $^{4}$He applying the shadow wave function (SWF) formalism [16, 17]. In addition to providing key information concerning the elastic properties, our results shed new light onto the possible role of dislocations in the experimental observation of the elastic stiffening of solid and its potential connection to the apparent superfluidity in this quantum crystal. Within the semi-discrete PN framework, a straight dislocation lying along the y -direction 2