"This will be my second bilateral visit there in two years, a sign of our strong relationship," he said in a Facebook post prior to his departure.
"During my visit, I will join the International Vesak Day celebrations in Colombo on 12th May, where I will interact with leading Buddhist spiritual leaders, scholars and theologians," PM Modi wrote.
He said it was an honour for him to join these celebrations with President Maithripala Sirisena and Prime Minister Ranil Wickremesinghe.
"My visit brings to the fore one of the most abiding links between India and Sri Lanka - the shared heritage of Buddhism," he said.
The Prime Minister recalled that during his last visit in 2015, he had the opportunity to visit Anuradhapura, a UNESCO world heritage site and a leading centre of Buddhism for centuries.
He said his trip will commence in Colombo with a visit to the Seema Malaka at the Gangaramayya temple where he will take part in the traditional lamp-lighting ceremony.
He will be meeting with Sirisena, Wickremesinghe and other eminent dignitaries, he said.
"I will also visit the up country region of Sri Lanka where I will inaugurate the Dickoya Hospital that has been built with Indian assistance, and have an interaction with the Indian-origin Tamil community," PM Modi said.