The efficiency and scour were studied around a breakwater composed of vertical pipes and rock fill under regular waves. Experimental research was done on transmission coefficient (kt), and sour. The variable parameter is increasing in rock fill height (Z) between two rows of piles and increasing in wavelength (L). Three models are studied: Z = 20, 30, and 40 cm, and the rock fill used is a coarse stone with a diameter of 4.5 cm and a porosity of 37%. As the relative rock fill heights grow (Z/h) from 0.5 to 1.0 and with a rising relative wave length (h/L) from 0.12 to 0.36, the transmission coefficient (kt) drops from 0.90 to 0.40. When (Z/h) was varied in the range (0.5–1) at (h/L) equal 0.36, the relative seaward erosion depth reached its maximum at (Dsmax/h) and ranged between 0.03 and 0.1. The increase in the height of rock fill the scour depth upstream. Additionally, for all models, the material harvesting pit was moved downstream.