The ability to change swimming styles and body positions, involving continuous shifting from horizontal to vertical posture and performing jumps, as well as technical skills play a fundamental role in water polo performance. To face with these demands, the coaching staff of elite and sub-elite water polo clubs might adopt a variety of training methods, also based on their specific coaching philosophies. This point has led to an enlargement of the staff, with higher head coaches’ responsibilities, who may interpret their professional activity according to their own coaching philosophy, education, and their respective national water polo schools. In fact, based on their international sports achievements, some countries can be identified as recognised water polo national schools. For this reason, the purpose of this study was to survey 40 head coaches of three important national water polo schools (Italy, Greece, and Serbia) to identify and compare their coaching philosophies and training methodologies. The survey was based on five sections (Technical staff composition, Team roster, Weekly periodization, Testing and monitoring, Tactics and strategies). Furthermore, using a detailed descriptive statistic, the current study gives interesting information on how 40 high-ranking elite and sub-elite teams of different national championships organize their training during a typical week of the competitive season. A further improvement of this research line could include more national schools, expanding the sample to more countries from all over the world.