Musaimeer Pump Station and Outfall project (MPSO) is a strategically important drainage asset initiated, developed, and completed by Ashghal in 2022. This project accommodates ground and storm water received from the drainage networks of 270 km2 of urban areas in southern Doha, along with storm protection for four soccer stadiums used during the FIFA 2022 World Cup. The key elements of this project were a pump station with a capacity of 19.7 m³ / s, one of the longest ground and storm water tunnels in the world with a total length of 10.2 km and the diffuser bed structure measuring 194 m x 40 m. The diffuser bed structure is connected to the outfall tunnel by a riser shaft and is the structure used to disperse the ground and storm water in a controlled manner and in accordance with environmental standards. This technical paper will detail the entire process from dredging and material stockpiling, riser shaft drilling and construction, diffuser bed fabrication onshore, transportation to final location, installation on the sea floor, backfilling and protection works and finally commissioning of the entire project.