Ocean shipping from Texas ports has grown with the development of the state's commerce and resources. Before 1845 Galveston and Velasco, the most important ports on the Gulf, engaged mostly in trade with New Orleans. In 1845 a total of 250 vessels arrived at Galveston, 52 of which were steamships. In 1855 this total had grown to 326, including 93 steamships. On both the regular runs between Galveston and New Orleans and the unscheduled runs to the Atlantic coast, most of the trade was of the common-carrier type, as opposed to the merchant-trader sort found in the early part of the nineteenth century. Galveston's principal export was cotton, two-thirds of which went to Britain. Other ports of importance before the Civil War were Brazos Santiago (at Port Isabel), Indianola, Port Lavaca, Corpus Christi, Port Aransas, and Sabine Pass. These ports were shallow and served principally as ports for intercoastal trade, which generally cleared at Galveston. Indianola was a possible exception to this, for as early as 1858, 125 beef cattle were shipped from there each week on average.
After the Civil War, port traffic expanded and numerous small towns along the Gulf Coast felt the stimulus of ocean commerce. Partially because of the rapid growth of rail connections in the 1870s and 1880s and partially because of the steadily increasing draft of oceangoing vessels, these shallow-water ports later suffered a decline, and many of them, like Indianola, vanished. About 1890, considerable political and commercial activity was directed toward the establishment of deepwater ports in Texas. Of the private efforts, perhaps the most ambitious was that of the Brazos River Channel and Dock Company, which proposed to dredge a forty-foot-deep harbor at the mouth of the Brazos and make the river navigable to Waco. Congressional appropriations were made for the survey of possible Texas harbors, and the harbor at Galveston was deepened. Improvements were made at Sabine Pass, Quintana, and Port Aransas. For the 1890s the average number of annual arrivals at Galveston was 290.
By 1910 Texas had four serviceable deepwater seaports at which thirty-five steamship lines maintained regular schedules. Galveston, as a result of large expenditures by the federal government, had become an important national port, and the total number of arrivals in that year was 1,672. The port of Sabine Pass, with five miles of waterfront and direct ship channels to Port Arthur and Beaumont, exported large quantities of lumber, cotton, and oil. Port Arthur and Beaumont, by virtue of channels to Sabine Pass, were also open to deepwater vessels. In 1910 some coastwise trade was carried on through Aransas Pass, Velasco, Corpus Christi, and Brazos Santiago, which had also received government appropriations. These expenditures on Texas harbors continued. In 1925 Galveston, Texas City, Freeport, Port Bolivar, Corpus Christi, and the Sabine ports of Port Arthur, Beaumont, and Orange were suitable for oceangoing traffic, and a ship channel was making Houston a port of the first magnitude. An intracoastal canal had been completed from New Orleans to Sabine Pass and from Galveston to Corpus Christi. By 1936 Port Aransas, Port Isabel, and Port Neches had been converted to deepwater ports, and the port of Houston, a man-made harbor, had become the most important port in Texas. In 1946 the Texas deepwater ports were Houston, Galveston, Texas City, Beaumont, Port Arthur, Orange, Sabine Pass, Corpus Christi, Freeport, Port Aransas, Ingleside, Brownsville, and Port Isabel. The total value of the traffic through these ports was $1,814,183,762. In 1946 also the Gulf Intracoastal Waterway was opened from Brownsville to Florida.
The 370-mile Texas Gulf Coast had become a major seaboard by 1954, when a total of 138,360,878 tons was shipped through twenty-six Texas ports. By 1959 this amount increased to 160,535,334 tons. For the 1954–63 decade Texas averaged $2,676,000,000 yearly in foreign trade ($2,113,000,000 in exports and $563,000,000 in imports), led all states in the export of chemical and petroleum products, and ranked second in agricultural products, fourth in food products, and eighth in manufactured items.
Port Mansfield, in Willacy County, became the thirteenth deepwater Texas port in 1962. The others were (in order of importance by shipping tonnage in 1971): Houston, Beaumont, Corpus Christi, Port Arthur, Texas City, Freeport, Port Aransas (Harbor Island), Brownsville, Galveston, Orange, Port Isabel, and Sabine Pass. These thirteen major ports accounted for 183,801,593 tons of the state's total shipping of 195,995,241 tons in 1971, with Houston alone handling over 68,000,000 tons of cargo. The port of Houston annually ranked second or third in the nation in tonnage among deepwater ports. Among the major shallow-water ports in Texas were Port Lavaca, Sweeny, Dickinson Bayou, and Rio Hondo-Harlingen. Traffic along the Gulf Intracoastal Waterway, which linked most of the major ports, continued a steady increase during the 1950s, 1960s, and early 1970s; short tons of commerce amounted to 24,700,000 tons in 1954, 34,000,000 in 1960, 55,500,000 in 1967, and 67,617,562 in 1971. Tonnage for the thirteen major ports in 1988 and 1989 was more than 81,000,000. In 1990 it was 71,000,000. Tonnage for all ports was 260,000,000 in 1982, 291,000,000 in 1987, and 330,000,000 in 1989. In 1990 the total of receipts and shipments for the thirteen largest ports was more than 321,000,000 tons and for all Texas ports more than 335,000,000 tons.