The latest tragedy – the third since Wednesday – came amid high smuggler activity not seen in Greek waters in months.
According to Athens News Agency, the coastguard found 16 bodies late Friday, including those of three women and a baby, and rescued 63 people from a boat that overturned and sank near the island of Paros.
Hours earlier, 11 bodies were recovered from a boat that ran aground on an islet north of the Greek island of Antikythera on Thursday evening.
Ninety people stranded on the islet were rescued, the coastguard said, according to AFP.
On Wednesday, a dinghy carrying migrants capsized off the island of Folegandros, killing at least three people.
Thirteen people were rescued, while dozens remain missing, Greek authorities said.
The UN refugee agency UNHCR said the Folegandros accident was the worst in the Aegean Sea this year.
"This shipwreck is a painful reminder that people continue to embark on perilous voyages in search of safety," said Adriano Silvestri, the UNHCR's assistant representative in Greece.
Earlier Friday, the coastguard had intercepted another boat with 92 men and boys on board after it ran aground on the coast of the Peloponnese peninsula.
Three suspected smugglers who fled the boat on foot were later arrested.
The UNHCR estimates that more than 2,500 people have died or gone missing at sea in their attempt to reach Europe from January through November this year.
Nearly one million people, mainly Syrian refugees, arrived in the European Union in 2015 after crossing to Greek islands close to Turkey.
"These days, the criminal activity of smugglers, who are indifferent to human life, has intensified, stacking dozens of distressed people, without life jackets, on boats that do not even meet the basic safety standards," Giannis Plakiotakis, Maritime Affairs Minister commented late Friday.