This paper proposes a low-cost ultrasound (US) based wireless power transfer (WPT) link for powering lowpower electronics devices used in underwater conditions. The proposed US-WPT link comprises a pair of low-cost ultrasonic transducers, one as a transmitter (Tx) and the other one as a receiver (Rx), and a low-cost full bridge rectifier circuit using Schottky diodes. The paper extensively discussed the modeling of the ultrasound devices, focusing on the energy harvesting perspective and also on designing a low-cost efficient rectifier to generate DC power from ultrasound signal received at the piezoelectric-receiver module. It also may be noted that the developed US-WPT link is capable of generating power wirelessly as high as 3.7 mW in underwater conditions. Therefore, it can be claimed that the overall design of the US-WPT link is quite simple yet highly efficient for immersible sensor nodes.