The saltiest ocean in the world is the Atlantic Ocean. The Atlantic Ocean has a higher average salinity compared to other major oceans such as the Pacific Ocean, Indian Ocean, and Southern Ocean. The salinity of seawater is typically measured in parts per thousand (ppt) or as a percentage. The average salinity of the Atlantic Ocean is around 3.5 to 3.7% or approximately 35 to 37 ppt. Salinity levels can vary within different regions of the ocean due to factors such as evaporation, precipitation, and freshwater inflows from rivers. It's important to note that while the Atlantic Ocean is generally considered the saltiest, there can be localized variations and pockets of higher salinity in other oceans depending on local conditions and factors.