Modi will be the Chief Guest at the UN-recognised 14th International Vesak Day meant to mark the enlightenment and passing away of Lord Buddha.
The visit follows the invitation of Sri Lankan President Maithripala Sirisena. It will be Modi’s second trip to Sri Lanka as Prime Minister after March 2015.
Modi will also pray at the Temple of the Sacred Tooth Relic at Kandy in central Sri Lanka as well as at a temple in Colombo.
The golden-roofed Kandy temple houses Sri Lanka’s most important Buddhist relic — a tooth of Lord Buddha.
Modi will also open an India-funded 150-bed multi-speciality hospital in the central hill district which is home to Tamil tea plantation workers of Indian origin.
Although no bilateral talks are scheduled, Indian officials said the visit was expected to expand the momentum in India-Sri Lanka ties.
Last month, Sri Lankan Prime Minister Ranil Wickremesinghe visited India.