Pine Island Glacier in West Antarctica is sensitive to changes in its oceanic and atmospheric environment because of its geometrical configuration, and it is known to be in a state of ice dynamical imbalance. Today, it is retreating, which eventually leads to continuous thinning and speedup of the glacier. Fluctuations in the glacier’s surface mass balance affect our ability to observe these dynamics, for example by affecting the penetration depth of the radar altimeter signals within the near-surface snowpack. We have collected an extensive record of ground-based and airborne observations along a 900 km traverse of the Pine Island Glacier as part of the UK NERC iSTAR-D project, to develop an improved understanding of the factors that affect satellite observations. The data set includes ground-penetrating radar, Ku-band phase-sensitive radar, Ku-band ASIRAS airborne radar, snow density measurements based on neutron scattering, and shallow and deep ice cores. We combine these measurements to determine patterns of snow accumulation across the traverse, as well as their variation in time: Reflectors in the uppermost 10s of metres of the glacier are tracked along the traverse in the various radar data sets and – assuming that each reflector stems from the same event – dated according to the ice core chronologies and annual layer counting in the density–depth profiles from neutron scattering. From these data, we then compute the mean accumulation rate along the traverse using each dated layer and their depth. The data allow us to evaluate the impact that fluctuations in surface mass have on the CryoSat-2 signal over the Pine Island Glacier.