The British Isles required four oil tankers of petroleum daily during the early war years, and most of it came from Venezuela, through Curaçao, after Italy blocked passage through the Mediterranean Sea from the Middle East.

The United States' Gulf of Mexico coastline, including petroleum facilities and Mississippi River trade, could be defended at two points.

The United States was well positioned to defend the Straits of Florida but was less able to prevent access from the Caribbean through the Yucatán Channel.

United States military aircraft production depended upon bauxite imported from the Guianas along shipping routes paralleling the Lesser Antilles.

The French island of Martinique was perceived as a possible base for Axis ships as British relationships with Vichy France deteriorated following the Second Armistice at Compiègne.

The September 1940 Destroyers for Bases Agreement enabled the United States to build airfields in British Guiana, and on the islands of Great Exuma, Trinidad, Antigua, and Saint Lucia.

U-502 sank crude oil tankers Monagas, Tia Juana and San Nicholas between Lake Maracaibo and Aruba.

U-156 entered San Nicolas harbour on Aruba and torpedoed oil tankers Pedernales, Oranjestad and Arkansas.

A Venezuelan gunboat, General Urdaneta, assisted in rescuing the crews of several torpedoed vessels; and A-20 Havoc light bombers attacked all three U-boats unsuccessfully; Resulting in an increased American occupation of the island began for its protection.

After leaving Saint Lucia, U-161 torpedoed Sarniadoc and sank the United States Coast Guard lighthouse tender USCGC Acacia with gunfire.

Kals ordered the shelling of several petroleum storage tanks but after only five shots, a Dutch shore battery responded which forced him to abort.

Later a German U-boat attacked a merchant ship off Curaçao and was engaged by Dutch anti-aircraft and naval gun batteries but again the submarine escaped unharmed.

She was transporting a load of random cargo from Pensacola, Florida to Venezuela when attacked by U-69 90 mi (78 nmi; 140 km) east of Bonaire.

Both torpedoes missed, so Graf ordered his crew to close the range to 2,200 yd (2,000 m) and to open fire with the deck gun at 03:47.

German U-boats sank two Mexican tankers, Potrero del Llano on 14 May by Reinhard Suhren's U-564 off Florida, and Faja de Oro on 21 May by Hermann Rasch's U-106 off Key West.

SS Sylvan Arrow was a tanker of the Standard Oil and Transportation Company during World War II when U-155 torpedoed her.

The tanker SS Hagan was sunk by U-157 on 11 June about 5 mi (4.3 nmi; 8.0 km) north of the Cuban coast.

[17][18][19] On 5 July 1943, 70 mi (61 nmi; 110 km) to the west of Port-Salut, Haiti, U-759 encountered the American-flagged steamer Maltran, which was part of Convoy GTMO-134.

A PBM Mariner flying boat first dropped a load of explosives over the sub, and then for seven hours American surface vessels depth charged the area, but U-759 escaped without damage or loss of life.

The German submarine submerged and attempted to flee but Thetis gained sonar contact and began a depth charge attack.

German submarine U-158 off Bermuda at Coordinates: 32°50′N 67°28′W / 32.833°N 67.467°W / 32.833; -67.467 on 30 June 1942 was sunk by a Martin PBM Mariner commanded by Richard Schreder.

The freighter SS Robert E. Lee was under escort by the American patrol chaser USS PC-566 45 mi (39 nmi; 72 km) south of the Mississippi River Delta on 30 July 1942.

First, an American PBY swooped down and bombed the U-boat, and then Canadian corvettes HMCS Halifax and Snowberry attacked.

After just barely capturing the vessel, the Canadian sailors realized the Germans had already scuttled the boat and it was taking on water.

The Canadians left U-94 and she sank with nineteen of her crew; Oakville rescued 26, including the commander, Oberleutnant zur See Otto Ites.

The crew was interrogated and provided valuable information to the U.S. Army[citation needed] Intelligence about U-boats and their submarine base at Lorient.

The aircraft dropped a smoke float over U-176, and the Cuban submarine chaser CS-13—under Second Lieutenant Alférez Delgado—picked up the enemy craft with sonar.

Stier was badly damaged as well and could no longer make steam, so her commander scuttled her less than two hours after defeating the American vessel.

The American gunboat USS Erie was escorting Convoy TAG-20 in the Caribbean between Trinidad and Guantánamo Bay when attacked 10 miles south of Curaçao by a German U-boat in November 1942.