  The boundary rigidity problem is a classical question from Riemannian
geometry: if $(M, g)$ is a Riemannian manifold with smooth boundary, is the
geometry of $M$ determined up to isometry by the metric $d_g$ induced on the
boundary $\partial M$? In this paper, we consider a discrete version of this
problem: can we determine the combinatorial type of a finite cube complex from
its boundary distances? As in the continuous case, reconstruction is not
possible in general, but one expects a positive answer under suitable
contractibility and non-positive curvature conditions. Indeed, in two
dimensions Haslegrave gave a positive answer to this question when the complex
is a finite quadrangulation of the disc with no internal vertices of degree
less than $4$. We prove a $3$-dimensional generalisation of this result: the
combinatorial type of a finite CAT(0) cube complex with an embedding in
$\mathbb{R}^3$ can be reconstructed from its boundary distances. Additionally,
we prove a direct strengthening of Haslegrave's result: the combinatorial type
of any finite 2-dimensional CAT(0) cube complex can be reconstructed from its
boundary distances.
