ommunication from within the steel pipeline by inspecting or sensing tools or robots is usually performed via a cable. As the length of the tether restricts the communication distance and as the cable may encumber the tool’s movement, we explore the feasibility of acoustic communication from within the liquid-filled pipe to an external sink through the steel pipe walls. The paper derives the sound signal attenuation resulting from the combination of the liquid content and metal wall acoustic channels. Results show that for 4” to 40” diameter steel pipes, acoustic communication of only a few hundred Hertz may be possible with low data rates, but multimedia communication prospects are weak. The paper also explores other wireless communication methods.