Pressure-retarded osmosis (PRO) is the promising technology to harvest sustainable osmotic energy from solutions with different salinities. Significant researches have been dedicated to develop various PRO membranes with great performances in the lab. However, in order to gain more understanding of the membrane performances and operating conditions beyond the lab-scale studies, pilot studies using large membrane modules and real water sources were urged to be conducted. This chapter introduces a novel pilot design by incorporating PRO with seawater reverse osmosis (SWRO) system. The PRO–SWRO hybrid system not only can reduce the overall energy consumption required for seawater desalination but also can mitigate the disposal and environmental issues of seawater brine. Different PRO feed pairs were tested and the results indicated that all feed pairs were capable of producing power densities ranging from 5 to 5.7 W/m². Several operation and maintenance strategies were investigated as well. Owing to the severe PRO membrane fouling induced by the wastewater retentate, regular membrane cleaning was necessary to recover the membrane performance. Other results from similar pilot tests are also briefly discussed in this chapter.