In the progressively used terrestrial and air-based Wireless Sensor Networks, Radiofrequency aids in the transmission of data and information. Nonetheless, from sensing followed by transmission in an underwater environment demands a completely contrasting technique to perform underwater communication. The oceans being the least unexploited, covering over 70% of the Earth’s surface is a source of vast resources. Still, the underwater world is unaffected less by the recent progressions in this field of WSN and their impact on the research and development. Growing practical difficulties burden the shifting of the many terrestrial and aerial WSNs state-of-the-art to the aquatic world advancements. Acoustics with sensors forms the key for many underwater deployments to tackle with the stringent environmental conditions of the oceans. However, different underwater environment demands different communication approaches for sensing and transmission. This paper emphases in broadening the scope of sensing in acoustic sensing incorporated multimodal sensors, paving the way to the progress of robust Internet of Things (IoT) applications and the key idea of this detailed review is to see UW-ASN from the perspective of IoT. A detailed overview and niche future research openings in UW-ASN and its deployments is presented aiming for novel architectures and protocols in the future, covering the bigger picture of Underwater Acoustic Sensor Network through better research and industrial advancements. © BEIESP.