Marine protected areas (MPAs) have been implemented to mitigate the effects of climate change and overfishing on various marine ecosystems. Nonetheless, these areas need monitoring to ensure their actual utility. Tools like acoustic tags are used to study the animals’ behavioural patterns and obtain valuable information to improve MPAs. Recently, new architectures have been proposed to overcome the inherent limitations of off-the-shelf tags, for example, by implementing bidirectional communication capabilities with the newly developed open protocol from European Tracking Network. In this paper, the testbed topology and methodology used to develop these bidirectional acoustic tags are discussed alongside the laboratory results achieved.