Surface grabs of suspended sediments from boils and the background flow in Squamish Estuary revealed strong differences between the two environments. Boils exhibit higher sediment concentrations and larger particle sizes than the background flow. The higher sediment concentrations and larger grain sizes in boils are related to tidal phase, with maximum concentrations and sediment sizes occurring in the early decelerating phase of the tidal flow. Sediment concentrations and grain sizes in the background flow are comparatively invariant with tidal phase. Boils appear to play an important, if not dominant, role in suspending and transporting sand-sized sediments in Squamish Estuary.