Wat Hat Yai Nai, formally Wat Mahattamangkalaram, is a temple beside U Tapao Canal near Hat Yai's inner market. Its major landmark is Phra Phuttha Hattha Mongkhon, a giant reclining Buddha.
Songkhla provincial and Hat Yai municipal records give the image a length of 35 metres, a height of 15 metres and a width of 10 metres. That scale is the reason to visit; this is not a complex where every part can be absorbed from one quick photograph.
The temple sits behind Hat Yai Nai Market, close to the canal, and remains a place for worship as well as sightseeing. Build the stop around the surrounding streets and traffic, wear appropriate clothing, and check current temple arrangements before going.