  With the advent of multi-wavelength electromagnetic observations of neutron
stars, spanning many decades in photon energies, from radio wavelengths up to
X-rays and $\gamma$-rays, it becomes possible to significantly constrain the
geometry and the location of the associated emission regions. In this work, we
use results from the modelling of thermal X-ray observations of PSR~J0030+0451
from the NICER mission and phase-aligned radio and $\gamma$-ray pulse profiles
to constrain the geometry of an off-centred dipole able to reproduce the
light-curves in these respective bands simultaneously. To this aim, we deduce a
configuration with a simple dipole off-centred from the location of the centre
of the thermal X-ray hot spots and show that the geometry is compatible with
independent constraints from radio and $\gamma$-ray pulsations only, leading to
a fixed magnetic obliquity of $\alpha \approx 75\deg$ and a line of sight
inclination angle of $\zeta \approx 54\deg$. We demonstrate that an off-centred
dipole cannot be rejected by accounting for the thermal X-ray pulse profiles.
Moreover, the crescent shape of one spot is interpreted as the consequence of a
small scale surface dipole on top of the large scale off-centred dipole.
