The U.S. Atlantic pelagic longline fleet pursues highly migratory species (e.g., swordfish, tunas, and sharks) over an extensive range in the Atlantic, Gulf of Mexico, and Caribbean Sea. Because of the fleet’s diverse range and vessel characteristics, fuel can be a major component of vessel operating costs and can make estimating fishing trip costs of the fleet difficult. A two part model was developed for this fleet to estimate fishing trip operating costs. Specifically, to address the importance of fuel and geographic range in trip costs, trip fuel consumption is modeled separately from other trip costs and fuel price is exogenous to the model. Trip fuel consumption was modeled as a function of trip distance, trip length, vessel length, vessel horsepower, and hull composition. Non-fuel costs were modeled as a function of trip length, crew size, target catch, geographic location, vessel characteristics, and inflation. A log-log regression was used to model both these functions using data from a random sampling of 20 percent of the fleet that are required to report economic information along with their fishing logbook submissions. This two part cost model is flexible enough to allow trip cost estimates even with changing fuel costs, fishing locations, and inflation.