The most popular floating market among tourists in Bangkok is the Damnoen Saduak Floating Market. This market is known for its vibrant and bustling atmosphere, colorful boats, and a wide variety of goods and food being sold from the boats. It has become somewhat of a tourist attraction and is often visited by travelers looking for a quintessential floating market experience in Bangkok. However, it's worth noting that there are other floating markets in Bangkok that are also popular among tourists, such as the Amphawa Floating Market and Taling Chan Floating Market.