The crew on the Irish Navy vessel LE Eithne rescued rescued 360 migrants - including nine children - from a rickety wooden barge in the Mediterranean.
The men, women and children on the barge were located in choppy waters about 31 miles (50km) north-west of Tripoli in Libya. They were all brought to safety during the three-hour rescue.
Within hours, the crew were involved in a second search and rescue operation, and 100 migrants on a rubber craft were located 70km north-west of Tripoli.
A Navy spokesman said all 460 migrants were provided with medical treatment, food and water on board the LE Eithne.
The vessel and crew were dispatched by the Irish Government in mid-May to assist Italian authorities in the humanitarian search and rescue operations off the North African coast.
Lieutenant Commander Eric Tymon said that many of those saved were suffering from the effects of sea sickness and excessive exposure to the sun.
"You could see the relief on seeing these Irish sailors arrive to take them off this unsafe raft to a safer place," he said. "We can only imagine what conditions they're actually fleeing from. You must put yourself in their minds to ask what would make them step into the vessel."