The partnership will help promote rugby development in Thailand, said England's legend Martin Johnson.
Johnson, who captained England to win the 2003 World Cup, said the Thailand Rugby Union would benefit a lot from the partnership.
With rugby returning to the Olympics at next year's Rio Games, the sport will receive more interest among Thais, he said.
"Rugby is a global sport and Thais will have a chance to learn more about this through the relationship between the two parties," he said.
"More students may take up the sport. Next year, there will be rugby at the Olympic Games and I want to see Thailand to be a part of it."
Jaturon Himathongkam, of Singha Corporation, said his company will sponsor the 12-team Premiership for two and a half years and this will benefit the sport in Thailand.
"We are the first Asian brand to be an official partner of the Premiership Rugby," he said.
He added that with England to host the 2015 Rugby World Cup in September, it is the right time to promote the sport here.
Dominic Hayes, commercial director of the Premiership Rugby, said that the deal will be good for both parties and that there are plans to help rugby development in Thailand.
Singha Corporation is also a sponsor of Manchester United and Chelsea football clubs. Bangkok Post