  We present two fiberized vector magnetic-field sensors, based on
nitrogen-vacancy (NV) centers in diamond. The sensors feature
sub-nT/$\sqrt{\textrm{Hz}}$ magnetic sensitivity. We use commercially available
components to construct sensors with a small sensor size, high photon
collection, and minimal sensor-sample distance. Both sensors are located at the
end of optical fibres with the sensor-head freely accessible and robust under
movement. These features make them ideal for mapping magnetic fields with high
sensitivity and spatial resolution ($\leq$\,mm). As a demonstration we use one
of the sensors to map the vector magnetic field inside the bore of a $\geq$
100\,mT Halbach array. The vector field sensing protocol translates microwave
spectroscopy data addressing all diamonds axes and including double quantum
transitions to a 3D magnetic field vector.
