Measurement of top-hole drill cuttings particle size distribution in offshore drilling from floating rigs is not straightforward because these sections are drilled without a marine riser. In two drilling operations, a riserless mud return system was used, which made it possible to measure the particle size distribution. Still, because of the reactivity between loose shale and water, such measurements are not simple. A measurement method was developed in the field during the drilling of these two wells. The development of this method is described to assist and simplify similar measurements in the future. Likewise, the results are presented to allow scientist to use proper particle size distributions in offshore cuttings spreading analyses.