The subsea cabled infrastructure of the Laboratori Nazionali del Sud of the Istituto Nazionale di
Fisica Nucleare (LNS-INFN) is continuously expanding, both in the number of observing systems
and in its capacity to host new assets. Since 2024, the historical Test Site offshore the port of
Catania, at 2100 m water depth, has been upgraded with the installation of a short-baseline, large-
bandwidth tetrahedral antenna, deployed in the framework of the IPANEMA project. In 2025, a
Distributed Acoustic Sensing (DAS) system acquired by the Centro Siciliano di Fisica Nucleare e
di Struttura della Materia (CSFNSM) under the VONGOLA project was permanently connected to
the underwater cable, enabling joint testing of complementary techniques for acoustic soundscape
monitoring and studies; both system are driven by the same master clock onshore. Meanwhile,
at the Capo Passero Site at 3500 m water depth—primarily dedicated to the KM3NeT/ARCA
detector—another DAS unit was connected to the main electro-optical cable under the European
Commission funded LowNoiser project. In addition, a set of three seafloor hydrophones, deployed
at relative distances of about 300 m, continuously streams data, allowing long-term studies
of noise in the band between a few tens of Hz and 70 kHz. Finally, a new subsea data and
power hub for multidisciplinary science, funded under the ITINERIS project, has been built
and will be deployed soon. Alongside this extensive hardware upgrade, several software tools
for soundscape analysis and sound cataloging have been developed, relying both on standard
digital signal processing methods and on new artificial intelligence techniques. A FAIR-oriented
approach for data preservation has also been implemented and shared with project stakeholders.
This combination of several acoustic sensors, multiple connection ports and advanced software
tools provides unprecedented opportunities to study the acoustic detection of ultra-high-energy
particles in the deep sea.