This article discusses the results of a survey that measured school teachers’ and mobile learning (m-learning) experts’ perceptions of the relative importance and effectiveness of various pedagogical principles underpinning m-learning designs. A scan of relevant literature produced a set of articles describing effective innovative m-learning. Principles underpinning the learning activities in these articles were identified. These principles were then provided to respondents so that they could identify the most important ones relative to the others for designing effective and innovative m-learning tasks. A rigorous Best/Worst Scaling (BWS) survey was used to collect these data. This is the first time that a BWS has been conducted with regard to mobile pedagogical principles. Findings showed that principles related to authenticity were rated most important relative to other principles by the m-learning experts and principles related to personalisation and customisation were rated most important by practising teachers. Other principles that have been used in innovative m-learning designs, such as gamification and intergenerational learning, were seen as least important by all respondents. The findings will inform design of professional development activities, in particular, those pertaining to an app being developed in an Erasmus + project, Developing and Evaluating Innovative Mobile Pedagogies (DEIMP).