Speed limits were introduced in the Lagoon of Venice in 2002 to reduce wave motion, which damages environmentally sensitive areas in the broader Lagoon as well as buildings in the city of Venice. In this paper, we estimate the welfare losses experienced by recreational boaters as a result of the speed limits. We fit a single-site travel cost model to a sample of boaters intercepted as they depart from or arrive to marinas and launching ramps on the Lagoon. Our Poisson model is corrected for truncation and endogenous stratification. We construct three measures of the price per trip, which allow us to check the sensitivity of models and welfare estimates to possible measurement errors in the opportunity cost of time. Our results are robust to the measure of price used and conservatively peg the welfare losses of boaters to 7.7-9.6 million per year. Even under conservative assumptions, the welfare losses of boaters are sufficiently large that, given current monitoring and enforcement of the speed limits, we believe there is a strong incentive for boaters to disregard the limits.