This course is organised by the IAHR Working Group on Transient Flows under the new IAHR Training Courses Series. The course programme has been designed to cover a broad selection of numerical modelling software for transient flows in pressurized systems. First an introduction to the basic background theory and modelling assumptions laying beneath standard engineering software are provided. Then a series of commercial and non-commercial software, open-access, freeware and payware, are presented showcasing their applicability by means of insightful case studies based on a variety of hydraulic systems such as hydropower schemes, water supply systems and industrial flows. The course completes with an open discussion convening the main takeaways on the role and limitations on the use of modelling software towards the design, protection, operation and maintenance of hydraulic systems affected by transient flows.