The goal of this paper is to assess the effect that the exposure to a service learning project carried out during the first-year Civil Engineering introductory course had on students’ academic motivation and personal, interpersonal and professional CDIO skills in a one-, three- and five-semester timeframe. The effect of the service-learning (S-L) project on students’ CDIO skills was measured with an instrument built by the authors (Effect of Service-Learning on CDIO Skills - ESLCS) and the academic motivation was measured using the Academic Motivation Scale (AMS). Both instruments were applied to four cohorts (2015, 2016, 2017 & 2018), during the second semester of 2018. Among some of the results, a very strong correlation was found between the perception that students had on the effect that the S-L project had on their CDIO skills, their intrinsic motivation and their identified regulation.