The steamship was arguably the most consequential technological change in the history of maritime transport.
This paper examines how the transition from sail to steam reshaped maritime transport and trade. We
identify the effect of steam on shipping times and cargo values using nearly 70,000 voyages arriving in
Barcelona, one of the largest ports in the Mediterranean. Our identification strategy leverages variation
across origins, months, years, ship-nationality, cargo types, and ship-masters. We show that steam reduced
travel times at sea by 68-72%. Steam also reduced time in port and the variance of travel time, indicating
widespread operation impacts. We also show that steam increased total cargo values by more than 46%
through greater volume shipment and by shifting cargoes to higher value products. At the same time,
a greater share of steamships at an origin led to a voyage-level decline in high value cargo, suggesting
steamships led to some substitution away from other ships. Our results demonstrate that the transition to
steam significantly increased trade value and shaped its composition in the first era of globalization.