First, it is said that Loi Krathong originated from Buddhism.

     That is, before the Lord Buddha became enlightened and became the Supremely Enlightened Buddha, he was staying under a Bodhi tree near the Neranjana River. One day, Sujata, an upasika, had a maid bring Madhupayasa rice (rice cooked with honey or sugarcane juice) on a tray.goldWhen he had finished eating, he made a vow that if he would one day become a Buddha, he would let the tray float upstream. With the power of his vow and his supernatural powers, the tray floated upstream to the navel of the sea, and then sank into the coils of the tail of the Naga, the guardian of the underworld.

     The Naga King woke up and when he saw what happened, he announced loudly that now another Perfectly Enlightened Buddha had appeared in the world. Then all the gods and the Naga King went to pay homage to the Buddha. The Naga King asked the Buddha to leave his footprints on the bank of the Neranjara River so that they could come up and pay homage. The Buddha did so, and the maidservants reported the news to Nang Suchada. Every year on that day, Nang Suchada would bring perfumes and flowers on a tray and float them in the water to pay homage to the Buddha’s footprints. Over time, this became the Loi Krathong tradition that we see today.

     Regarding the imprinting of the Buddha’s footprint, some say that the Naga king invited the Buddha to preach the Dharma in the Naga realm. When he was about to return, the Naga king asked for a monument from him to worship. The Buddha prayed and imprinted his footprint on the sandy beach of the Nammatha River, and the Nagas worshiped the Buddha’s footprint on his behalf. Later, Buddhists learned about this and continued to worship the Buddha’s footprint by placing offerings in krathongs and floating them in the water. As for floating krathongs on the full moon day of the 11th month or the end of Buddhist Lent to celebrate the anniversary of the day the Buddha returned to the human world after staying in the Tavatimsa heaven for 3 months to teach Abhidhamma to his mother, it is because on that day, countless deities and Buddhists came to welcome him with offerings. It was also the day that the Buddha opened heaven and hell to the public by his power, so people floated krathongs to celebrate the Buddha’s arrival.

     For the motto that The reason for floating the Krathong with candles to worship the Phra Kesa Kaew Chulamani in the Tavatimsa heaven is said to be because it coincides with the day that the Lord Buddha left to become a monk on the banks of the Anoma River. He used his sword to cut off the topknot of his hair, which floated into the air as he had wished. Indra therefore brought a glass casket to contain it and enshrined it in the Chulamani Chedi in the Tavatimsa heaven. (According to Pradeep, this means lighting a candle or lighting a fire in a lamp/lighting bowl or small clay bowl) which in the north of us often release floating lanterns or lanterns called fire kites into the air to worship Phra Kesa Kaew Chulamani.

The second story According to the Brahmin texts, the teachers say that

     The Loi Kratong or Following Kratong ceremony was originally a Brahman religious ceremony performed to worship the three gods: Shiva, Vishnu, and Brahma. It is a type of ceremony that goes hand in hand with Loi Krathong. Before floating the Kratong, there must first be following the Kratong, which according to ancient Indian scriptures is called "Deepavali" By astrologically determining that when the sun reaches Scorpio and the moon is in Capricorn, then it is time for the lantern. And when the worship has been completed for the specified day, then the lantern is taken to float in the water. Later, Buddhists saw that it was a good thing, so they changed it to worship the Buddha's footprint and welcome the Lord Buddha as mentioned above. They usually take the 12th month or Yi Peng month as the criterion (Yi Peng is the second month according to the Lanna calendar, which counts the months according to the lunar calendar, 2 months earlier than the central region). 

The third story is about Burma.

     It is said that once during the reign of King Ashoka the Great, he wanted to build 84,000 pagodas, but was always obstructed by the Mara. So he went to ask an Arahant, Phra Upakut, for help. Phra Upakut then went to ask the Naga King of the underworld for help. Phra Naga agreed and successfully defeated the Mara King. King Ashoka the Great Therefore, the pagoda was successfully built as desired. Since then, on the full moon day of the 12th month, people will hold a Loi Krathong ceremony to worship the virtues of the Naga. Some sources say that the Naga is Phra Upakut who lives at the navel of the sea and has great power, so he can defeat the devil. Phra Upakut is highly revered by the Burmese and northern Thai people. 

The fourth story comes from an ancient belief in Lanna that

     There was a cholera outbreak in the Hariphunchai Kingdom, causing many people to die. Those who did not die migrated to Thaton and Hanthawaddy for 6 years. Some had families there. When the cholera subsided, some returned. On the anniversary of their migration, they prepared incense and candles to pay homage, along with the above mentioned consumer goods. Sapao (Read as "Sa-pao", meaning ship or krathong) floating down the river to remember relatives in the city of Hongsawadi. The floating of krathong is done on the Yi Peng day, which is the full moon of the twelfth lunar month. It is called "Loi Khom", but it is not common in Lanna. Mostly, during the Yi Peng festival, Lanna people will have a ceremony to establish the royal dharma or a long sermon like the Mahachat sermon. And there is a widespread lighting of lanterns. (The floating of krathong, which in ancient Lanna is called "Loi Khom", the word "Khom" is pronounced "Kha-mode", which is the name of a forest ghost. It likes to go out to eat at night and has a fire that can be seen at intervals, similar to a Krasue ghost. Therefore, it is called "Loi Khom" according to the characteristics of the krathong that has a candle floating in the water, seeing a faint reflection similar to a Khom ghost.)

The fifth story is that in ancient China,

     In the north, during the rainy season, the water always floods. Some years, hundreds of thousands of villagers died from the flood and their bodies could not be found. Therefore, the people prepared food-filled krathongs to float in the water as an annual offering to the ghosts. As for the ones floating at night, it is believed that they wanted to make it look solemn and dark to make it look sacred because it was about ghosts and spirits, and ghosts do not like to appear during the day. The reason for lighting candles was because the road to the ghost town was dark, so they had to be lit to provide light so that the ghosts could return easily. In Chinese, floating krathongs is called “letting gom nam” (pang chui teng), which is the same as “loying khom” in Thai. From the above story, we can see that floating krathongs is mostly an act of showing gratitude and remembering those who have done us favors, such as the Buddha, gods, the Goddess of the River, and ancestors. It also shows gratitude (repaying favors) by paying homage with various offerings, especially by worshipping the Buddha or the Buddha’s footprints. This can be considered a kind of moral principle that tells Buddhists to follow in the Buddha’s footsteps, which are symbols of all goodness.