The booming aviation sector is worldwide increasingly faced with capacityconstraints at both the land and air side. In recent years various countries have tried toovercome the land-based bottlenecks by the design and construction of new offshoreairports. This paper aims to identify and assess the critical success factors for tworecently built island airports, viz. in Hong Kong and Osaka. The analysis addressessuccess conditions at both the corporate and the regional level. The methodologicalbasis for the comparative investigation deploys the so-called pentagon prism. Theresults show that island airports may seem to offer a favorable land use andenvironmental solution, but face at the same time severe financial and maritimeecology problems.