Wat Buppharam, also known locally as Wat Plai Khlong, is Trat's most important historic temple. The compound sits a little west of the town centre and rewards a slow look: old wooden structures, painted interiors, and a calm that is very different from the bus station and ferry offices.
It is not a blockbuster temple, and that is the point. Come in the morning, dress respectfully, and treat it as a short, grounding stop before the island rush begins.