The aim of this study is to test whether marine diatom remains recovered from archeological fishing implements (fishing nets and metal fishhooks) found at pre-Hispanic sites of the Huanchaco coastline, north coast of Peru, can be used as indicators to infer whether they were used, and if yes, how they were used by ancient fishermen before their burial ritual. The combined analysis and quantification of fragmented and complete diatom valves from the fishing implements and control samples, which can help to identify potential contaminations from soil deposits, can indicate if the fishermen used them in their daily subsistence activities. This study can help to infer which marine zones were exploited by these ancient fishermen. Marine diatom analysis results were combined with identificated fish species consumed and later discarded in the site's middens. An interesting pattern emerges from the preliminary results of combining both datasets: while all fishing nets were intensively used, metal fishhooks seem to have been very occasionally sunk in the sea. Although these results could simply be the outcome of the type of materials tested and conservation issues, it prompted us to evaluate how fishing technology was used during the first part of the Early Intermediate Period (100–400/450 cal. A.D.) along the north coast of Peru and its impact on the daily subsistence activities of ancient pre-Hispanic fishing settlements.