Opera surtitles have not received much attention within Translation Studies – not even within the field of multimedia translation, in which they belong – and it is the purpose of this paper to deepen our understanding of this translation type. The communicative context closely determines textual strategies for surtitles, which are constrained by technical, format and timing factors. And the function of surtitles – helping comprehension without too much interference with the overall reception of the opera sung in the original language – also affects their textual form. This paper will compare the translation strategies adopted by some opera houses from various countries, in order to show how different ways of implementing operational norms and of negotiating the constraints imposed by the transmission channel and by reception factors produce different surtitles in the same language. The analysis will force us to challenge some traditional concepts used in the study of translation.