Underwater filming in the Venetian canals is a complex undertaking, and you’re right to be concerned about water quality and logistics. Realistically, the visibility in the canals is likely to be very limited due to sediment and pollution. You’d need to carefully assess the location and potentially use specialized lighting and camera equipment to capture usable footage. The water can also pose health risks, so it’s important to take precautions such as protective gear and vaccinations. If you still want to, consult with a
Video crew Venice with underwater experience in similar conditions. They can advise you on the practical challenges and help you navigate the permitting process, as well as provide the correct equipment.