The LST-542 class ships, also known as tank landing ships (LSTs), were originally built by the United States during World War II. Several countries have operated these ships after their initial service with the U.S. Navy.

1. United States: The original operator, with numerous LST-542 class ships commissioned during the war.
2. Greece: The Hellenic Navy acquired several LSTs after World War II.
3. Turkey: The Turkish Navy also operated LST-542 class ships, enhancing their amphibious capabilities.
4. Philippines: The Philippine Navy received a number of these vessels for use in their maritime operations.
5. South Korea: The Republic of Korea Navy included LST-542 class ships in its fleet for amphibious operations.

These ships served various roles in each of these navies, often being refitted and modified to meet specific national needs. The LSTs were valued for their ability to transport troops, vehicles, and supplies directly to shore without the need for docks or piers.

If you need more specific details about their service history in any of these countries or information on particular vessels, feel free to ask!