Ultrasonic immersion testing enables researchers to learn about a sample’s microstructure through quantitative wave propagation metrics. Generally, the calculation of wave speed and attenuation requires the test piece to be smooth so that the reflection of wave packets is well- described by analytical expressions and does not cause distortion. This is achieved by mechanically polishing and grinding the sample to a level suitable for ultrasonic testing. However, mechanical polishing may be viewed as violating the nondestructive nature of ultrasonic testing. It can also distort the geometry of pieces and impart local damage. This is important since many manufactured materials, particularly additively manufactured samples, are rough as they are produced. While techniques such as electropolishing exist to improve the surface finish, for certain applications, polishing methods can alter the function of the sample. This project aims to examine the influence of surface roughness on measured longitudinal wave speed and attenuation. By examining samples with known surface roughness values before and after surface modification, the influence of roughness parameters may be quantified. This will provide important context on the role of surface roughness in attenuation and wave speed measurements. Furthermore, we seek to develop alternative measurement procedures to remove the effects of roughness-induced attenuation, improving the inspection of as-manufactured materials.