For better readability of the table, pass into the landscape mode.
The Gulf Coast comprises of the coasts of Texas, Louisiana, Mississippi, Alabama, and Florida which border the Gulf of Mexico. Here's the map. We've covered Florida separately as there is so much diving, compared to the limited diving in the other states.
In Texas and Louisiana, there is mainly lake diving and scuba parks where buses, cars etc. have been sunk. These are great for learning, but for real diving, go to the Flower Garden Banks National Marine Sanctuary.
During the January/March period, it's not unusual to see large schools of Scalloped Hammerhead sharks. Scientists don’t truly know the reason for this seasonal schooling, but have noted that it’s a regular occurrence in this part of the Gulf of Mexico and that all of the sharks appear to be male! Schooling Spotted Eagle Rays are also frequent visitors. While everything you’ll see at Flower Garden Banks National Marine Sanctuary is pretty amazing, there are some events that truly stand out. Dive operations who offer diving in the sanctuary are:
July, August and September bring the possiblity of seeing Whale Sharks. They seem to prefer the calmer surface conditions typical of that time of year as they cruise along gulping great quantities of plankton.