Is the Gulf of Mexico Salt Water? Yes—Highly Saline and Connected to the Atlantic

The Gulf of Mexico is a saltwater marginal sea of the Atlantic Ocean. Connected via the Straits of Florida (between Florida and Cuba) and the Yucatán Channel (between Mexico and Cuba), it shares Atlantic salinity.

Average salinity: 36 parts per thousand (ppt)—slightly higher than open ocean (35 ppt) due to high evaporation and limited freshwater inflow relative to volume. Surface area: 1.55 million km²; average depth: 1,615 m. Bordered by U.S., Mexico, Cuba.