This paper investigates the influence of an unsaturated layer in a soft soil on the dynamic response of piles subjected to an incident wave field caused by a vertical surface load. The free field response is compared to the response of single floating and end-bearing piles, and different configurations of square end-bearing pile groups. Simulations are made using a finite element model with perfectly matched layers where the incident wave field is computed from a separate source model employing a subdomain formulation. The presence of the unsaturated layer results in a resonance phenomenon in the top layer, amplifying critically refracted waves as they reach the surface. The associated response is shown to be significantly lower for concrete piles subjected to the same incident loading and practically independent of the pile end condition, in contrast to the response associated with the incident surface waves. For small end-bearing pile groups, the response caused by surface waves are further reduced while the response due to layer resonance show no further reduction. As a consequence, the frequency content associated with the layer resonance might constitute the dominating part of the vertical velocity response for end-bearing pile groups.