Leo Varadkar's father Ashok Varadkar, a doctor, moved to the United Kingdom in the 1960s.
Ireland Prime Minister Leo Varadkar left for New Delhi on Wednesday afternoon after celebrating the New Year in Goa, an official said.
Mr Varadkar, who is on a private visit to India, stayed at a plush resort in North Goa district to welcome 2020. He arrived in the coastal state on Monday.
"His entire trip was private and he did not even avail any police security for it," a senior police official said.
The Irish prime minister flew in an Air Asia flight from the Dabolim Airport in Goa to New Delhi in the afternoon, he added.
On Sunday, Mr Varadkar, who is of Indian origin, visited his ancestral village Varad in the coastal Sindhudurg district of neighbouring Maharashtra along with his family members.
It was his first visit to the village, said Mr Varadkar, who became prime minister of Ireland in June 2017.
His father Ashok Varadkar, a doctor, moved to the United Kingdom in the 1960s.
The visit was a "special moment" as three generations of his family gathered at Varad, the Ireland prime minister said after the villagers felicitated him.