This dataset contains data and code used in the manuscript “Parasites of the hermit crab Pagurus hirsutiusculus; distribution, prevalence, and thermal ecology”. Further details about the methodology is located in the manuscript and its supplementary material. This data is meant to inform our understanding about what parasites are present in the host Pagurus hirsutiusculus, as well as what factors control their abundance. This study also investigates how parasite infection affects host thermal response. Hermit crabs were surveyed for prevalence and occurrence at a variety of sites from Calvert Island down to Southern Vancouver Island from August 2020 - September 2021. Host relative abundance, salinity, and host size were measured at the sites. DNA sequence data from three different parasites were obtained from Calvert Island, Quadra Island, and Maple Bay during this sampling period. Metabolic rate was measured at 5 temperatures (12°C, 17°C, 22°C, 27°C, 32°C) in Pagurus hirsutiusculus infected by Peltogaster sp. and uninfected individuals in a laboratory at the University of British Columbia. Survival was recorded at ambient seawater conditions (12°C), and post temperature experiment. Moulting was also recorded at ambient seawater conditions. Additionally, this dataset contains occurrence and prevalence records of Peltogaster sp. found during a review of the literature conducted in the summer of 2020.