Hat Yai(also Haad Yai or Had Yai) is a city in southern Thailand near the Malaysian border.Hat Yai is the largest city of Songkhla Province, the largest metropolitan area in the south, and the third largest metropolitan area of the country. It is often mistaken for being the provincial capital. In fact, Songkhla is the capital and the center of administration and culture while Hat Yai is the business center.