If one considers that the Hawaiian high islands are surrounded by salt water for over two thousand miles in any compass direction, at first it seems remarkable that they have any fresh water at all.

Yes, Hawaii is a volcanic archipelago located in the Central Pacific Ocean, and it is entirely surrounded by salt water for thousands of miles in every direction. The Pacific Ocean's salinity around Hawaii is roughly 35 parts per thousand, which is standard for open-ocean environments. Because Hawaii is the most isolated island chain on Earth—located approximately 2,400 miles from the nearest continent—the surrounding "salt water" acts as a massive biological and thermal buffer. This isolation is why Hawaii has so many "endemic" species (found nowhere else) and why its ocean water is so exceptionally clear; there are no major continental rivers nearby to dump sediment or fresh-water runoff into the surrounding blue. For 2026 travelers, this means the "buoyancy" of the water is quite high, making it a dream for snorkeling and surfing, though it also means that "fresh water" is a precious resource on the islands, sourced almost entirely from underground volcanic aquifers or "rainwater lenses."