Two children were among three people who died early on Thursday when a migrant boat sank near the Greek island of Samos, the coastguard said.
At least 12 people including one more child are believed to have been in the boat.
The two young boys died shortly after being rescued, while the body of a man was recovered shortly afterwards, the coastguard said.
More than 200 refugees and migrants have died in 2019 while trying to cross the Mediterranean, the majority headed to Italy, according to the International Organization for Migration.
Greece is hosting over 70 000 mostly Syrian refugees and migrants who have fled their countries since 2015.
The island of Samos, in the eastern Aegean Sea near the Turkish coast, has one of the country’s most congested camps, with some 4 000 people crammed into a facility originally built to house fewer than 700.
Conditions at Greek island camps have been repeatedly criticised by rights groups. The Greek government says the problem is partly caused by a huge backlog of refugee asylum applications.