The main goals of this study were to understand the different roles played by teachers and students during a school-guided tour to an aquarium and to analyse their different perspectives about the visit. The study focused on students' and teachers' behaviour during school-guided visits to an aquarium; students' and teachers' perspectives about this type of school visits; and the reasons provided by teachers to engage in a guided tour to a science museum. Direct observations of 39 guided tours were performed in order to describe the structure of the visit and the participants' behaviour. A questionnaire was given to 145 teachers and 191 students after the visit, in order to describe their perspectives about the visit, and an online questionnaire was sent to a sample of 11 teachers, in order to understand their ideas about school visits to science museums. Data analysis showed that the guided visits, although well evaluated by both students and teachers, were mainly guide-directed and lecture-oriented, giving students and teachers very little choice and control over the learning agenda. Moreover, teachers showed a very passive role during the visit and reported limited plans for preparation and follow-up activities that would support the visit. Despite this scenario, the teachers who were questioned preferred guided visits to non-guided visits and recognized the potential of museums for learning. The possible role of teachers in establishing the necessary connection between guided tours and school science, and helping to bridge school curriculum, museum content, and student inquiries is discussed.