The main ceremonies features boats of 8-10 metres in length, formerly made of banana wood or bamboo, but now sometimes of other materials. The boats are filled with offerings such as kao tom mut (sticky rice sweets wrapped in banana leaves) and decorated on the outside with flowers, candles and lamps. The boats are launched in the evening.
Additionally, some celebrants individually launch their own, smaller vessels. Boat races also take place around this time in many places throughout the country.
The phenomenon known as the Naga fireballs, in which glowing egg-sized balls rise out of the Mekong river, is most often reported around the night of Wan Awk Pansa. A clear reason for the fireballs has yet to be determined.
Vassa (Thai พรรษา, pansa or phansaa), also called Rains Retreat, is an intensive meditation retreat during the rainy season lasting for three lunar months from July to October.
It is followed by two of the major festivals of the year among Theravada Buddhists, including WanAwkPansa.
The focus of celebration by the laity is the first day of vassa, Wan Kao Pansa, during which worshippers donate candles and other necessities to temples, a ceremony which has reached its most extravagant form in the Ubon Ratchathani Candle Festival.