Montserrat is at great risk from the economic impact of climate change on its international transportation sector, which brings nearly all of its visitors (mainly tourists) from the main markets in North America and Western Europe and moves virtually all of its merchandise trade. The presence of a ‘persistently active’ Soufrière volcano into, at least the next decade worsens the situation. The total cost of climate change on international transportation in Montserrat was calculated by combining the impacts of changes in temperature and precipitation, new climate change policies in advanced countries, sea level rise and an eruption of the Soufriere Hills volcano. The impact for air transport could range from US$630 million (SRES B2 scenario), to US$742 million (SRES A2 scenario) and for maritime transport impact estimates range from US$209 million (SRES B2 scenario) to US$347 million (SRES A2 scenario). For international transport, as a whole, the impact of climate change varies from US$839 million under the SRES B2 scenario to US$1,089 million under the SRES A2 scenario. While further study is needed to examine in more detail the potential impacts of climate change on the two key international transportation assets - John A. Osborne Airport and Little Bay - the findings of this preliminary assessment are so important that transportation decision makers should begin immediately to assess them in the development of transportation investment strategies in Montserrat. Mitigation strategies to deal with green house gas (GHG) emissions from international aviation and shipping are especially challenging, because the 1997 Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) specifically excludes these from developed countries’ national targets. Instead, countries are expected to work through the International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO), but so far neither organization has reached agreement on binding actions, and many key issues remain unresolved.