Buddhists in Sri Lanka celebrating Poson Poya today (June 16 2019) at Jaya Sri Maha Bodhi & Ruwanwelisaya in Anuradhapura District, Sri Lanka. Poson, also known as Poson Poya, is an annual festival held by Sri Lankan Buddhists celebrating the arrival of Buddhism in Sri Lanka in the 3rd century BC. On a day like today, during the reign of King Devanampiyatissa, and Indian Emperor Dharmashoka, Buddhism was introduced to Sri Lanka by Mihindu Maha Arahath Thero and followers who traveled to Sri Lanka from Dambadiva (India).
Religious observances are held across the island to mark this significance.

Most celebrations are centered around Anuradhapura, Mihintale and Polonnaruwa as the King Devanampiyatissa met Arahath Mihindu Thero at Mihintale. Various religious activities are carried from the dawn at the eight sacred religious locations(Atamasthana).

The Sri Lankan government has officially declared a week (from 13 - 19) to celebrate Poson Festival through out the Island.