The yacht carrying 93 people was located about 40 nautical miles west of the small town of Pylos, the coastguard said in a statement.
There were no reports of missing passengers.
Six of the passengers were picked up by another yacht in the area and taken to Pylos, where one woman was transferred to hospital in the southern city of Kalamata.
Another 87 people were picked up by two passing tanker ships and transported to Kalamata, escorted by coastguard patrol vessels, the statement said.
The area is near where a deadly migrant shipwreck in June left hundreds of people dead and missing and led to allegations that Greek authorities had failed to respond appropriately to rescue the passengers.
The overcrowded trawler had set sail from Libya with an estimated 500-700 people on board.
Only 104 survived and 82 bodies were recovered.
The rest sank with the trawler in what is one of the deepest parts of the Mediterranean.
About 100 migrants rescued after Greece shipwreck – in pictures
Last week, 40 survivors filed a lawsuit in Greece against “all parties responsible”, saying Greek authorities failed to rescue passengers before the vessel capsized.
Many of the survivors dispute the official account that repeated offers of assistance by the coastguard were rejected, and claim a botched effort was made to tow the vessel to safety shortly before it capsized and sank.
Many use small dinghies to head from Turkey to Greek islands near the Turkish coast, while others use larger sailing boats, yachts or fishing vessels to make the longer crossing from either Turkey or North Africa to Italy, bypassing Greece.
The Greek coastguard said that a total of 115 migrants were rescued from three small boats off the eastern Aegean Sea island of Lesbos on Wednesday, and another 24 people off the island of Samos.