Texas State vs Federal Waters: The 9-Mile Line Explained

The fish you can legally keep off the Texas coast can change in the space of a single boat ride. Reel in a red snapper a few miles out and the rules are one thing; reel in the same fish a little farther offshore and the season, the bag limit, and the legal size can all be different. The reason is an invisible line 9 nautical miles from the beach, where Texas state waters end and federal Gulf of Mexico waters begin. Here is what that line is, who draws it, and how it quietly governs every offshore trip out of Freeport and the Brazosport area.

Where do Texas state waters end and federal waters begin?

Texas state waters run from the shoreline out to 9 nautical miles, and federal waters begin past that line and reach to 200. That 9-mile limit is unusually wide. Most Gulf states control only the first 3 nautical miles, but Texas, like the Gulf coast of Florida, claimed three marine leagues, about 9 nautical miles, before it joined the United States in 1845, and it kept that boundary. Texas Parks and Wildlife patrols state waters out to 9 nautical miles in the Gulf of Mexico (TPWD: Fishing in Federal Waters).

The practical effect is that a Texas angler gets a wider band of state water than almost anyone else on the Gulf, and that extra water is where a lot of the rule confusion starts.

How far is 9 nautical miles, really?

Nine nautical miles is about 10.4 statute miles, which is far enough that you cannot judge it by eye from the deck. In a typical offshore boat it is a run of roughly 30 to 60 minutes depending on the hull and the sea state. Because the line is invisible from the water, the only reliable way to know which side of it you are on is GPS, which is why every serious offshore boat runs a chartplotter and why the captain, not your gut, calls the zone you are fishing.

Who manages each zone, and why does that matter?

Two different authorities manage the two zones, and that split is the root of every difference in the rules. Inside 9 nautical miles, Texas Parks and Wildlife sets and enforces the regulations. Past 9 nautical miles, the waters are federal, managed by NOAA Fisheries together with the Gulf of Mexico Fishery Management Council, the regional body that writes the federal reef-fish rules for the Gulf of Mexico under the Gulf Reef Fish Fishery Management Plan. The Council’s jurisdiction runs from 9 to 200 nautical miles off Texas.

Because the state and the federal Council develop their measures separately, the same fish can be governed by two different rulebooks depending on where it is caught. That is not a loophole or an oversight. It is two governments managing the same ocean from different mandates.

Why do the rules change at the line?

Seasons, bag limits, and size limits change at the line because each authority sets its own, and the gap can be large. Red snapper is the textbook case: in Texas state waters the season is open year-round with a 4-fish limit and a 15-inch minimum, while in federal waters the season is limited and the limit drops to 2 fish at a 16-inch minimum (TPWD red snapper regulations). We break down the snapper seasons and dates in detail in our Galveston red snapper season guide.

It is not only an offshore-species issue. Inshore, state-managed species follow Texas rules entirely, including seasonal closures you will not find in any federal rulebook, like the flounder rules and the November closure covered in our Texas flounder regulations guide. The pattern holds across species: know the zone, then know whose rulebook applies.

How do you know which water you are fishing?

You know by distance from shore on GPS, and the fish is judged by where you are fishing, not where you launched. This is the part that catches visitors out. If your boat runs past 9 nautical miles, you are under federal limits for everything you catch out there, even if you trailered in that morning from a Texas ramp. And anything you carry back to a Texas dock has to meet Texas possession limits too, regardless of where it was caught (TPWD Outdoor Annual).

On a charter, there is one more layer. A federally permitted for-hire boat fishes under the captain’s federal reef-fish permit, and that permit governs the trip. If you are paying to fish on a licensed Galveston or Freeport charter that runs offshore, you are on the federal program, and federal limits apply to everyone aboard.

What else changes past the line?

Past the line, federal reef-fish conservation rules apply on top of the bag and size limits. The most important one for offshore anglers is fish handling: deep-water reef fish like snapper and grouper suffer barotrauma when reeled up fast, and a federal rule enacted under the DESCEND Act required anglers to keep a descending device or venting tool rigged and ready when targeting reef fish in Gulf of Mexico federal waters (NOAA Fisheries). That provision was set to sunset in early 2026, so confirm the current requirement with NOAA before your trip. Either way, carrying and using one of these tools is the right call for any fish you plan to release from deep water, and we cover the how-to in our descend-device guide.

What this means for a Brazosport or Freeport trip

For a real trip out of Freeport, the line decides what kind of day you are booking. A nearshore, state-water trip inside 9 nautical miles fishes under Texas rules, which for snapper means a longer season and a higher bag at a smaller size, and it is a shorter, weather-friendlier run. A full-day offshore charter crosses into federal water for the bigger fish on deeper structure, and trades into the federal season and limits to get there. Neither is better. They are different trips under different rulebooks, and knowing which side of the 9-mile line you will fish is the first thing to settle when you plan one.

When you book, ask the captain plainly which waters the trip fishes and which limits apply. A good operator will tell you before you ever leave the dock.