Geophysical testing to determine depth and integrity of sheet piles, while straightforward in theory, is often influenced by unanticipated site conditions. While ASTM D7400-14, Standard Test Methods for Downhole Seismic Testing, provides an outline of survey techniques (including specifications of ideal survey geometry) for traditional borehole seismic and vertical seismic profiling (VSP) surveys, adaptation of the methods for parallel seismic surveys to determine vertical extent and condition of deep foundations often requires project-specific variations of parameters. For parallel seismic surveys, a borehole is drilled and grouted in accordance with ASTM D7400-14, optimally at a distance of 1–3 m from the target. In practice, limitations on well placement and budget, as well as the presence of pervasive cultural noise, impose constraints. In addition, unanticipated surface and subsurface physical conditions can negatively influence data collection approaches and data quality. Significant sources of seismic noise are universally present at heavily industrialized sites where VSP investigations to characterize deep foundations are performed. Noise sources can overwhelm generated seismic signals and obscure desired wave arrivals. The ideal seismic source location is directly on the top of the sheet pile, but access is often restricted by thick concrete pile caps. To overcome such challenges, we approach problems with multiple investigation methods, innovative placement of sources, and careful interpretation. Here, we present case studies of parallel seismic surveys to determine depth and integrity of sheet pile quay walls where major site limitations introduced significant ambiguity in interpretation. We reduced ambiguity by adding a complementary suite of borehole magnetometer and hydrophone surveys to supplement data collected in the ASTM-required triaxial geophone survey. Through application of a multi-method approach and extensive processing, integration, and analysis of data post-collection, we were able to present a reliable interpretation of the survey results.