The 2015 U.S. West Coast domoic acid event was caused by a massive harmful algal bloom (HAB) that consisted mostly of the diatom Pseudo-nitzschia australis. It was unprecedented in its toxicity and geographic extent and resulted in extended and widespread closures of the lucrative commercial Dungeness crab and popular recreational razor clam fisheries. The fishery closures led to federal fisheries disaster declarations and generated an economic shock for coastal communities that depend on access to these marine resources. This study reports on the socioeconomic impacts of the 2015 HAB across 16 fishing communities on the U.S. West Coast using primary survey data. The survey instrument, deployed in the summer of 2017, collected information on sociodemographic and economic factors hypothesized to confer resilience or vulnerability to HABs, data quantifying individual impacts, and the coping and adaptive actions taken by individuals to deal with the event. The vast majority of survey participants (84%) were negatively impacted by the 2015 HAB, but individuals employed in fishing-related occupations experienced greater financial, emotional, and sociocultural impacts than those employed in other sectors. Further, those employed in fishing-related occupations were less likely to recover financial losses suffered as a result of the event. This study identifies the pathways through which HABs affect fishery-dependent and fishery-associated sectors of U.S. West Coast communities. The understanding gained can help inform efforts to prepare for future HABs, mitigate their socioeconomic impacts, and aid recovery.