Home to the capital city and nearly a million people, the island of Oahu in the state of Hawaii, USA, is highly dependent on external resources. Over the past decade, large-scale agricultural production has diminished dramatically, leaving the island greatly reliant on imports for food and most other basic goods. A strong tourism sector and high levels of affluence contribute to per capita municipal waste generation rates exceeding all other U.S. states. The only municipal landfill requires immediate expansion if it is to remain in operation, and it has proven extremely difficult to find additional disposal sites. An island-wide material flow analysis (MFA) was performed as an innovative means of considering issues of import, export, consumption, and substitution, resulting in long-term strategies for diminishing the generation of waste that could complement current local conservation and recycling efforts. The findings indicate several opportunities for using domestic waste resources to substitute for imports and simultaneously reduce waste generation, particularly for construction materials. Legislative constraints and possible changes in this regard are also considered. Although past efforts by both the city and state governments to encourage on-island recycling and reuse have not achieved set goals, the MFA results suggest numerous opportunities that could be pursued to increase material self-sufficiency and/or reduce waste disposal by several hundred thousand short tons, enhancing the long-term sustainability of the island.