Fu, Q.; Wang, N.; Lin, W.-N., and Wu, N., 2018. Comparing the environmental effects of terrestrial and offshore airports: The case of Dalian City, China. In: Wang, D. and Guido-Aldana, P.A. (eds.), Select Proceedings from the 3rd International Conference on Water Resource and Environment (WRE2017). Journal of Coastal Research, Special Issue No. 84, pp. 103–108. Coconut Creek (Florida), ISSN 0749-0208.To increase an airport's capabilities, it is a common practice to expand the airport and add a new runway. However, this expansion occupies more land and space and produces more noise from aircraft, which can be a nuisance to surrounding residents. There are many cities facing this problem, with one being Dalian City in northern China. Unlike many inland cities, Dalian City is a peninsula city surrounded by sea on three sides with abundant marine resources, but limited land. Therefore, building a new offshore airport away from the urban core has been proposed as an effective solution to remit the contradiction of urban and environment. It is necessary to evaluate the effects of offshore airport construction on the marine ecology and terrestrial airport construction on urban lives. In this paper, from the perspective of lost value, the environmental effects of expanding the existing terrestrial airport and of building an offshore airport on the marine environment are compared by conducting many field investigations on Dian International Airport site selection. The results show that the offshore airport plan would be distant from the urban core than the terrestrial airport plan, and the effect of offshore airport plan aircraft noise on surrounding residents would be small, as would its effect on fish in surrounding areas. Therefore, compared with expanding the terrestrial airport, establishing an offshore airport could effectively improve the urban environment and decrease the adverse effects on the marine ecosystem. This result is valuable for airport site selection for Dalian City and provides guidance for airport site selection for other coastal cities.