Paraguay's naval forces were first developed under Francia, who kept a fleet of eleven vessels. Under the presidencies of both Lópezes, the navy was expanded to include both a marine battalion and a naval artillery element. The navy played a significant role in the early part of the War of the Triple Alliance. Using the steam warship Tacuari, naval forces in early 1865 helped capture the Argentine city of Corrientes, then battled an attacking Brazilian fleet, first losing and then regaining control of the city. After finally forcing the Brazilian fleet to withdraw to Riachuelo, the Paraguayan navy attacked again in one of the world's largest riverine naval engagements. Although the battle was inconclusive, the navy's losses forced it to withdraw upriver. Thereafter, the navy fought a series of holding actions until 1868, when its forces had been almost completely destroyed.

For the fifty years following the end of the occupation by Brazilian forces in 1876, the navy remained very small. In response to tensions with Bolivia, however, it was upgraded in the late 1920s, adding a small air arm in 1929 and acquiring new vessels in 1931. The fleet's role in the Chaco War, however, was limited largely to carrying troops and supplies on the first leg of the journey into the Chaco and to supplying antiaircraft cover for the army. Some naval officers also saw service as ground force commanders. In addition, the naval air arm carried out important reconnaissance and support missions and undertook in 1934 the first night air raid in the Western Hemisphere.

After the Chaco War, the navy inventory grew slowly the primary acquisitions were patrol boats donated by the United States in 1944. The naval aviation arm benefited from donations by the United States and Argentina in the 1950s. The fleet was augmented in the 1960s and early 1970s with three United States-manufactured minesweepers acquired from Argentina. During the same period, the United States transferred or leased to Paraguay a variety of craft, including launches, landing craft, tugs, and support vessels. These were purchased outright during the 1975-77 period. The only major acquisition during the 1980s was a Brazilian-built river gunboat commissioned in 1985.

As of late 1988, naval personnel numbered some 3,150, of whom approximately one-third were conscripts. These included personnel assigned to the fleet, to naval aviation, and to a battalion of marines, as well as members of the coast guard and the harbor and port police.

The ship inventory consisted of six river defense vessels, seven patrol craft, and three amphibious vessels, in addition to various support, transport, and cargo vessels (see table 11, Appendix). The bulk of the fleet was antiquated: five of the six river patrol vessels were laid down in the 1930s the newest was of 1980s vintage. One large patrol craft had a wooden hull and first saw service in 1908.

The main naval base was located in the capital at Puerto Sanjonía and included a dockyard and the naval arsenal. Secondary bases were located 849 d across the Río Paraguay at Chaco I and at Bahía Negra and Puerto Presidente Stroessner.

The 500-strong marine battalion included both a regular and a commando regiment. It was headquartered at Puerto Sajonía, but most personnel were stationed on the upper Paraguay at Bahía Negra and Fuerte Olimpo.

The small naval air arm had only some fifty-five personnel assigned to it. It flew primarily utility and training aircraft as well as a few helicopters. Most equip,ment was located at Chaco I, although the helicopters sometimes were detached to two vessels that had helicopter platforms.

The navy was also responsible for the coast guard, which maintained navigational aids and guarded major river crossings. Some 250 naval personnel manned four batteries of coastal defense guns on the upper part of the Río Paraguay. The harbor police, which regulated the merchant fleet, was also under the navy's control.

After training at the military academy in Asunción, naval officers were sent to Argentina for advanced training in Argentine naval schools and on the Argentine fleet vessels. Enlisted personnel received basic and advanced naval training at Puerto Sajonía, some were also sent to Argentina to train.

Data as of December 1988