Turkey's coastguard on Monday detained around 150 migrants as they attempted to sail from the country's western coast to the Greek island of Lesbos, state media reported.
Acting on a tip-off, the authorities stopped 101 immigrants from Afghanistan, Pakistan and Syria as they were about to set off from the Turkish town of Ayvacik in the western Canakkale province.
They were taken into custody pending deportation, the official Anatolia news agency reported.
Later on Monday the Turkish coastguard detained 48 more migrants off the town of Ayvalik in Balikesir province as they tried to head to Lesbos.
Those migrants, including women and children, were from Yemen, Syria, Afghanistan, Myanmar and Eritrea, Anatolia said.
Turkey, which is already sheltering 1.8 million refugees from the Syrian civil war, has become a key transit point for people seeking a better life in Europe.
Many pay people smugglers thousands of dollars to travel towards EU states in small boats, but the journey is fraught with danger.
In the first half of 2015, more than 68,000 migrants, more than half of them from Syria, have risked the short trip from Turkey to the Greek islands, according to UN figures.