The airlift pump has been around since the late 18th century, yet it is rarely seen or used in industry. Recently, the aquaculture industry has shown great potential for the use of airlift pumps operating under two-phase flow conditions to increase the operating efficiency of such facilities. This thesis presents both numerical and experimental investigations of the operation and performance characteristics of an airlift pump system. Experimental verification was also performed of an airlift pump that was integrated with a fish farm raceway in an aquaculture facility. Utilizing the Volume of Fluid (VOF) multi-phase model along with the K-ε turbulence model, a numerical study using ANSYS Fluent 19.0 was performed for the two-phase flow hydrodynamics in airlift pump injectors. The study was carried out for both the two-phase flow in the pump riser, and for the flow in an open channel raceway. Also, the performance of the airlift pump was evaluated experimentally for a 2.54 cm dimeter airlift pump in the lab. The numerical results were found to be in agreement with the experiments within ±20%. These simulation results were used to scale an airlift pump to operate in a 3.5 m3 raceway system. The numerical results had an average RMS agreement of ±15% with the experimental results. The present study was found to present a great tool for optimizing the airlift pump performance, as well as modifying the design of future aquaculture systems or other two-phase flow applications