This list ranks the busiest seaports by cargo tonnage, which refers to the total mass, or in some cases the volume, of cargo transported through each port. The rankings are based on AAPA world port data.

The cargo rankings based on tonnage should be interpreted with caution, since these measures are not directly comparable and cannot be standardized into a single unit. In the Measure column, MT = Metric Tons, HT = Harbor Tons, FT = Freight Tons, and RT = Revenue