Both SEAL Team 4 and SEAL Team 6, the predecessor to DEVGRU, participated in the US invasion of Grenada. The SEALs' two primary missions were the extraction of Grenada's Governor-General and the capture of Grenada's only radio tower. Neither mission was well briefed or sufficiently supported with timely intelligence and the SEALs ran into trouble from the very beginning. One of their two transport planes missed its drop zone, and four SEALs drowned in a rain squall while making an airborne insertion with their boats off the island's coast. Their bodies were never recovered.
After regrouping from their initial insertion the SEALs split into two teams and proceeded to their objectives. After digging in at the Governor's mansion, the SEALs realized they had forgotten to load their cryptographic satellite phone. As Grenadian and Cuban troops surrounded the team, the SEALs' only radio ran out of battery power, and they used the mansion's land line telephone to call in AC-130 gunship fire support. The SEALs were pinned down in the mansion overnight and were relieved and extracted by a group of Marines the following morning.
The team sent to the radio station also ran into communication problems. As soon as the SEALs reached the radio facility they found themselves unable to raise their command post. After beating back several waves of Grenadian and Cuban troops supported by BTR-60 armoured personnel carriers, the SEALs decided that their position at the radio tower was untenable. They destroyed the station and fought their way to the water where they hid from patrolling enemy forces. After the enemy had given up their search the SEALs, some wounded, swam into the open sea where they were extracted several hours later after being spotted by a reconnaissance plane.