Gulf Intracoastal Waterway - Texas Route Segment

Sabine River, TX to Brownsville, TX

The Texas portion of the Gulf Intracoastal Waterway has its start at 30°03.2’ N / 93°43.2’ W (MM 266.0 WHL) on the Sabine River which divides Texas from Louisiana.

From the Sabine River, the Texas GICW runs for 415.5 miles starting out in a generally southwesterly direction before gradually turning to the south near Aransas, TX before ending in Brownsville, TX at 25°57.1’ N / 97°24.1’ W (MM "681.5 WHL") very near the Texas / Mexico border.



The Texas Gulf Intracoastal Waterway is marked with your standard Aids to Navigation which also display yellow triangles or yellow squares. When southwest and south bound along the Texas GICW, marks displaying yellow triangles should be kept on your starboard hand and those marked with yellow squares should be kept to port.

While typically the yellow triangles will be found on red markers and yellow squares are found on green markers, caution should be exercised along this route in the vicinity of the Sabine River, Galveston Bay, Chocolate Bay, Port O’Conner, Victoria Barge Canal, and Port Isabel where the GICW intersects or coincides with the channels marked by the Lateral Buoyage System.


NOAA chart coverage of this portion of the GICW beginning at (MM “266.0 WHL”) to (MM “681.5 WHL” is provided by charts #11331, #11324, #11322, #11319, #11315, 11314, 11308, 11306, 11303, and #11302. These charts can be viewed by clicking on the links below:

Chart #11331 - Ellender to Galveston Bay
Chart #11324 - Galveston Bay Entrance
Chart #11322 - Galveston Bay to Cedar Lakes
Chart #11319 - Cedar Lakes to Espiritu Santo Bay
Chart #11315 - Espiritu Santo Bay to Carlos Bay
Chart #11314 - Carlos Bay to Redfish Bay
Chart #11308 - Redfish Bay to Laguna Madre
Chart #11306 - Laguna Madre to Chubby Island
Chart #11303 - Chubby Island to Stover Point
Chart #11302 - Stover Point to Brownsville

Distances and Mileages

All distances along the Texas Gulf Intracoastal Waterway are given in statute miles unless otherwise noted. Statute miles are used in order to conform to the distances shown on the small craft charts typically used along this route.

This portion of the GICW between the Louisiana State line and the Mexican border is measured based on increasing mileage West of Harvey Lock from (MM “266.0 WHL”) to (MM "681.5 WHL").


The Federal project depth for the Texas portion of the Gulf Intracoastal Waterway provides for a minimum channel depth of 12 feet. Even though every effort is made to maintain the project depth, the actual controlling depths in the channels may vary due to shoaling reducing the available water depth until maintenance dredging can be accomplished.


Bridges, Locks, & Overhead Power Lines


A total of 13 bridges cross the Gulf Intracoastal Waterway in the state of Texas. The fixed bridges (10), all have vertical clearances of 73’ or better with the exception of the "State Road 361 Bridge" in Aransas Pass, TX having a clearance of only 48’. An alternate channel does exist that allows this bridge to be bypassed if necessary.

The (3) operating bridges all have closed vertical clearances between 0’ and 8’ that will prohibit most vessels from passing through without an opening. All guard VHF Channel 13.

Gulf Intracoastal Waterway Bridges - Texas (GIWW)

Port Arthur to Freeport

Mile Marker Bridge Charted Vert. Clear. Schedule Restrictions VHF
287.7 WHL Gulf Gate Bridge 136’ Fixed Bridge    
289.0 WHL West Port Arthur Bridge 73’ Fixed Bridge    
319.3 WHL High Island Bridge 73’ Fixed Bridge    
357.5 WHL Galveston Causeway RR Lift Bridge 8’ / 73’ Opens on Demand   13
357.6 WHL Gulf Freeway Bridge 73’ Fixed Bridge    
393.8 WHL Surfside Beach Bridge 73’ Fixed Bridge    

Gulf Intracoastal Waterway Bridges - Texas (GIWW)

Freeport to Brownsville

Mile Marker Bridge Charted Vert. Clear. Schedule Restrictions VHF
397.6 WHL Bryan Beach Bridge 73’ Fixed Bridge    
418.0 WHL Carney Creek Pontoon Bridge 4’ Opens on Demand Small Boat Passage 13
440.7 WHL Market Street Bridge 73’ Fixed Bridge    
533.5 WHL SR 361 Bridge 48’ Fixed Bridge    
552.7 WHL JFK Causeway Bridge 73’ Fixed Bridge    
665.1 WHL Queen Isabella Bridge 73’ Fixed Bridge    
666.0 Port Isabella Pontoon Bridge 0’ Opens on Demand   13

The table above lists the bridges, their schedules, and restrictions along the Texas Gulf Intracoastal Waterway from the Sabine River in Texas southwest to the Mexican Border.

This list is believed to be accurate as of January 2019. If any errors or omissions are noted, please e-mail us at with any corrections or recommendations.

This bridge operating schedule can be downloaded for your personal and private use as a ZIP file. The file contains the schedule in Adobe (.pdf) file format.

Texas Gulf Coast Bridge Schedule - Download


Texas Gulf Intracoastal Waterway Locks

Mile Marker Bridge Charted Vert. Clear. Schedule Restrictions VHF
441.1 WHL Colorado East Lock   On Demand Pleasure Craft on the hour. 13
442.0 WHL Colorado West Lock   On Demand Pleasure Craft on the hour. 13
Overhead Power Lines

Numerous overhead cables cross the Texas Gulf Intracoastal Waterway. The minimum authorized clearance of overhead cables crossing the GICW is 61 feet and is also found at Aransas Pass, TX at (MM 533.1 WHL.)

Caution - Many of the overhead cables over the waterway carry high voltage, and an extra margin of safety should be allowed when the weather is threatening.


Tidal ranges are fairly small along the Texas coast. Under normal conditions the mean range of tide averages about less than 1.5’ at Sabine Pass to about 0.5’ at Port O’Conner and across the remainder of the state to Port Isabel.

Texas typically experiences a "Mixed Tide" - exhibiting (2) unequal high and low tides each day.

Inlets and Passes

There are more than (17) Passes (Inlets) between the Gulf of Mexico and the inside waters of Texas. Most of these are only suitable for shallow draft vessels or local knowledge, but many can be considered navigable by most vessels.

Sabine Pass

Sabine Pass is a deep water entrance leading north to Port Arthur, Beaumont, and Orange, Texas. The entrance has jetties, is deep (40’), and well-marked with lighted buoys and ranges. The approach channel is marked with a lighted buoy RW "SB" Mo (A).

The most prominent features when approaching Sabine Pass are the "Sabine Bank" light (Q 30ft 5M), the "East Jetty Light" (Iso 2s 42ft 8M), and an abandoned lighthouse located on the east side of the entrance.

The Gulf Intracoastal Waterway intersection is located 15.8 miles above the entrance at (MM “288.6 WHL”).

Galveston Entrance

Galveston Entrance is wide (1.3 NM) well-marked with lighted buoys and ranges with jetties protecting both sides of the entrance. The entrance opens into Bolivar Roads a large deep water area in the entrance between Bolivar Peninsula to the north and Galveston Island to the south.

The approach to Galveston is marked by lighted buoy RW "GA" Mo (A) at 17.1 NM from the end of the jetties and lighted buoy RW "GB" Mo (A) is at 9.2 NM.

Prominent features on approaching Galveston Entrance include a 363’ building south of the entrance on Galveston Island and an abandoned lighthouse on the north side of the entrance. North Jetty Light (Iso R 6s) and South Jetty Light (Iso G 6s) displayed on 30’ towers mark the entrance.

The Gulf Intracoastal Waterway intersects at 7.7 miles above the entrance at (MM “350.8 WHL”). An alternate GICW channel also intersects 5.3 miles above the entrance at (MM “352.3A WHL”).

Brazos Harbor Entrance

Brazos Harbor Entrance is the entry point for the town of Freeport, TX, known locally as Brazosport. The entrance is well marked with lighted buoys and lighted ranges. The approach to the entrance is marked with a lighted buoy RW “FP” Mo (A). The entrance is deep with a least depth of 45 feet available to the Upper Turning Basin. Brazos Harbor Entrance intersects the GICW about 1.5 miles above the entrance near (MM “395.0 WHL”).

Matagorda Bay Entrance

Matagorda Bay Entrance lies 63 NM SW of Brazos Harbor Entrance. It leads to Port Lavaca and Point Comfort about 21 NM above the entrance. The entrance is deep with a least project depth of 36 feet found as far as Point Comfort, has jetties on both sides of the entrance, and is well-marked with lighted buoys and ranges.

The approach is marked by RW ”MSC” Mo (A) approximately 18 NM SE of the entrance and by RW ”MB” Mo (A) lighted buoy lying about 2.6 NM SE of the entrance. Matagorda Bay Entrance Light (28°25'18''N., 96°19'06''W.), 64 feet above the water, is shown from the E jetty. at the entrance to Matagorda Bay.

Strong current flows (8+ knots) can be found at the peak of the flood or ebb currents in the entrance and large whirlpools have been documented at the channel width transition points of the channel.

The GICW intersects the Matagorda Shipping Channel 5.2 miles above the entrance near (MM "471.1 WHL").

Aransas Pass

Aransas Pass is the primary approach from the Gulf of Mexico to Aransas and Corpus Christi TX. The approach to Aransas Pass is marked by buoy RW “AP” Mo (A), 4.8 NM from the entrance. The entrance channel is deep with a project depth of 45 feet to Corpus Christi, it is well marked with lighted and unlighted buoys and daybeacons, and lighted ranges. It is protected by jetties on both sides with San Jose Island to the north of the entrance and Mustang Island to the south.

A lighthouse, 67 feet showing Iso 2s light during the day and Iso 2s G at night high located on Harbor Island will be sighted during your approach to the pass.

Two GICW intersections exist in this area:

The Brazos Santiago Pass is the approach to Port Isabel and Port Brownsville, TX at the lower end of Laguna Madre. The entrance lies between Padre Island to the north and Brazos Island to the south. It is deep, with a least project depth of 36 feet, the channel is well-marked with lighted and un-lighted buoys and daybeacons along with lighted ranges, it also has jetties extending out close to 1 mile from the entrance. The approach is marked by a buoy RW “BS’ Mo (A) about 2.2 miles from the entrance.

The major navigation light is "Port Isabel Light," 91 feet showing a fixed white light.

Brazos Santiago Pass intersects the GICW at (MM “668.4 WHL”) 4.6 miles above the entrance.

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