Quick coupling valves are commonly used to make an easy and quick connection/disconnection of a sprinkler to/from the supporting pipeline. However, significant headloss occurs during the operation of the irrigation system by this valve. In the present study, water flow through a standard quick coupling valve was numerically modelled by computational fluid dynamics (CFD). In addition, different turbulence models were run to determine the effect of any component of the valve on flow characteristics. Comparison between numerical and observed data from the experiments on the prototype confirmed the validity of standard k‐ε as a high precision model. Three‐dimensional numerical simulation of the steady‐state flow under different rates of flow showed that the spring had the least negative effect among the installed components inside the quick coupling valve. On the other hand, the body length of the valve, especially the length of the inlet part of the valve, played the main role in the pressure drop. Unexpectedly, the installed sealing O‐ring reduced the headloss. Moreover, an effective modification was carried out on the components of an ordinary valve by increasing by 20 mm the length of the valve from the inlet side and modifications in trim elements. Finally, the findings revealed that 50% of headloss occurred in the developed valve compared to the ordinary type regardless of the flow rate.