The number of studies on goals and the analysis of how they are scored is increasing as they are considered to be the main indicator of futsal performance. Observational tools are changing including new variables that establish game patterns and that offer a better explanation to the internal logic of this sport. Thus, the creation and validation of an ad hoc observational tool in order to analyse offensive actions that end in goal is necessary. This is a detailed, nomothetic and multidimensional study. Intervention is nonparticipative with a complete degree of perceptivity. Five experts took part in this process. During season 14-15, 41 teams (16 Spanish, 11 Italian and 14 Russian) from the three main European leagues (240 Spanish league, 109 Italian league and 273 Russian league) performed 4716 offensive actions ending in goal in 622 matches. Footage of the football matches were provided by the different leagues via free internet platforms. The Observational Analysis of Futsal (OAF-I) observational tool has passed all the necessary tests with regard to its reliability and validity obtaining figures greater than .85 and being organized into 26 criteria and 324 categories.