It was the fourth time in his eight years of Prime Ministership that Singh was abroad on his birthday.
Today, he was en route to Frankfurt in Germany on his way back from New York.
A workaholic, Singh usually shies away from celebrating his birthday.
Singh, who was born in Gah in Punjab, which is now in Pakistan, says he does not know his actual date of birth but September 26 was given as birth day by his parents while getting him admitted in a school.
On previous such occasions, his birthday was celebrated on Air India One.
In his first year as Prime Minister in 2004, he celebrated his birthday mid-air on way to Geneva from New York on Air India`s Boeing 747-400.
Singh then did not cut the two-and-a-half kg fruit cake specially made for the occasion but joined everyone in having a slice of it.
He had then told accompanying reporters "I really don`t know my birthday. This is the date mentioned in my school records."