Every November, on the night of the full moon, Thailand sets its rivers alight. Most visitors head to Chiang Mai, where the sky fills with lanterns and the streets fill with people. An hour and a half down the road, Lampang does something different. Here, families float Sapao: small ships of bamboo, banana leaf and paper, with sails, candles and offerings on board. On festival night the Wang River fills with them, drifting slowly past the town's century-old bridge. It's the same full moon, but a quieter, more local celebration. This guide covers when Lampang's festival takes place in 2026, what happens each night, where to watch, and how to make the most of it.