WHY PACIFIC AND ATLANTIC OCEAN DON'T MIX The Pacific Ocean and the Atlantic Ocean actually do mix, but very slowly and with boundaries that make it look like they don’t. REASONS WHY PEOPLE OFTEN SAY THEY "DON’T MIX" > Ocean Water Has Different Properties: The Pacific and Atlantic have differences in salinity (salt content), temperature, and density. When waters with different densities meet, they create a visible boundary or "front" that makes it seem like they’re not mixing. > Ocean Currents an