The charming village of Ampawa is 10 km (7 miles) by songthaew from Samuk Songkram has a floating market similar to (but smaller than) that in Damnoen Saduak on Friday, Saturday, and Sunday evening from 5 to 9. The food market in the street adjacent to the canal starts at around 1 pm. Featured in a Thai movie, popular fireflies tours allow you to enjoy both the market and the beautifully insect-lighted trees. The bugs are best seen from May to October and in the waning moon. The hour-long tours usually run every half hour from 6:30 to 9 pm. You can arrange a tour directly at the pier (B650 for a boat) or through your hotel (around B70 per person). Unless you have private transportation, you'll have to spend the night in Ampawa, as the last bus back to Bangkok is in the early evening.
Samut Songkram, Thailand