Abstract: Data used in Lane, SJ, BW Tobalske, AL Moran, CM Shishido, HA Woods (2018) Costs of epibionts on Antarctic sea spiders. Marine Biology 165, 137 https://doi.org/10.1007/s00227-018-3389-9. Data sets include (1) measurements of drag on individual sea spiders with or without epibiotic barnacles and other fouling; (2) data on locomotion by fouled and unfouled sea spiders; (3) functional diffusion coefficients of oxygen through fouled and unfouled cuticle; and (4) levels of oxygen at the cuticle surface of fouled and unfouled individuals.