Pan trapping proves to be an effective method for field surveying insects, especially Diptera. This manuscript examines the effectiveness of the method for the rapid bioinventory of freshwater shoreline insects. Pan traps at ground level, above ground, and elevated and of different colors were evaluated for their ability to attract and capture insects. Abundance (n), taxonomic richness (T), and hierarchical diversity indices (H′) allowed for the determination of efficacy among methods. Yellow pan (n = 141, T = 10, H′ = 1.15) and elevated yellow pan traps (n = 113, T = 5, H′ = 1.18) were most effective at capturing the highest diversity of insects. Blue (n = 12, H′ = 1.18) and green (n = 51, H′ = 0.74) traps had similar richness (T = 4); however differed in the total insects captured and diversity. The results provide entomologists in South Texas and other subtropical environments with information to assist them with planning surveys in the field and with further study potentially developing pollution tolerance values for different insect taxa.