This book includes high-quality research papers presented at the Second International Conference on Wireless Sensor Networks, Ubiquitous Computing and Applications (ICWSNUCA, 2026), which is held at Gokaraju Lailavathi Engineering College, GRIET Campus, Hyderabad, India, during 20 21 February 2026. This book focuses on the applications, use-cases, architectures, deployments, and recent advances of wireless sensor networks as well as ubiquitous computing. Different research topics are illustrated in this book, like wireless sensor networks for the Internet of Things; IoT applications for eHealth; smart cities; architectures for WSNs and IoT, WSNs hardware and new devices; low-power wireless technologies; wireless ad hoc sensor networks; routing and data transfer in WSNs; multicast communication in WSNs; security management in WSNs and in IoT systems; and power consumption optimization in WSNs.