Although fishing is one of the most widespread activities by which humans harvest natural resources and reshape ecosystems, its global footprint is poorly understood and has never been directly observed. We processed 22 billion Automatic Identification System (AIS) messages and tracked >70,000 industrial fishing vessels from 2012-2016, creating a global dynamic footprint of fishing effort with two to three orders of magnitude higher spatial and temporal resolution than previous datasets. Our data show that industrial fishing occurs in >55% of ocean area and has a spatial extent more than 4 times that of agriculture. We find that global patterns of fishing have surprisingly low sensitivity to short-term economic and environmental variation and a strong response to cultural and political events such as holidays and closures.