For all its importance, we still lack a comprehensive quantitative assessment of the Suez Canal’s opening in 1869. Here, we find that it led to a 72% relative increase in bilateral exports for affected country pairs, suggesting a 12% permanent increase in world trade. With respect to the composition of trade, Suez was associated with large, concentrated changes in export shares for particular goods categories. Finally, with respect to mechanisms, the relative cost of using steamships on Suez-affected routes fell dramatically and immediately after 1869, pointing to a vital role for the canal in the diffusion of steam technology.