12 migrants drowned after their boat sank off the Turkish town of Ayvacık in Çanakkale province, news reports said on Saturday.
25 other migrants who were also on the boat were rescued, local news agency said.
Thousands of refugees – mostly fleeing war-torn Syria, Afghanistan and Iraq – attempt daily to cross the Aegean Sea from nearby Turkey, a short but perilous trip by inflatable boats, often in rough seas.
Earlier in the day, the Greek coast guard said four people, one woman and three children, drowned after their rubber boat capsized off a Greek island. One child was missing after the incident.
The coast guard said it has rescued 13 people and was searching for the missing child after the boat capsized off the Aegean island of Kalymnos.
Almost 400,000 people have arrived in Greece this year, according to the UN refugee agency UNHCR, overwhelming the cash-strapped nation’s ability to cope.
On Thursday, seven people, among them a baby and three children drowned after their wooden boat and a coast guard vessel crashed during a migrant rescue operation off the island of Lesbos.