The WE-EXPERTH project aims to study the parallel and simultaneous water entry (WE) of two spheres impacting on a water surface. The physics of WE and of parallel WE is important for a variety of engineering and natural science applications, such as underwater or navy vehicles, coating and spraying processes, marine platforms such as floating offshore wind turbine platforms, invasive free-surface flow measurement devices used in the steel industry, synchronized-diving athletes or plunge-diving birds. Scientific research in this area may lead to measures to reduce slamming loads on marine vessels and platforms, improve the accuracy of free-surface instrumentation, or even explain, why a diving bird does not get injured when it collides with water at high speed. Parallel WE is a highly nonlinear and unsteady process and has thus far not been addressed by research. Interactions are expected to influence air entrainment cavities and pinch-off (which can strongly affect the impact forces and the objects' kinetics) as well as splash curtains and jets (often undesired in engineering applications). During WE-EXPERTH we aim to analyze experimentally (by High-Speed-Camera/PIV/IMU) and theoretically the parallel WE of hydrophilic/hydrophobic spheres and significantly extend current knowledge by investigating the interaction of the involved physical phenomena, analyzing spheres' critical distance and spheres' kinetics for numerous scenarios. WE-EXPERTH brings together an experienced researcher with knowledge in WE, a supervisor with a background in theoretical fluid mechanics, and a host research group with experience in experimental research and image processing. This fellowship will be major step for the fellow towards full-professorship and will enable both fellow and host to continue WE-research beyond the scope of this project. Dissemination efforts will not only focus on scientific communities but also on broader audiences by producing explanatory slow-motion videos.