Australia and Tuvalu recently signed a unique treaty called the Australia-Tuvalu Falepili Union Treaty, on climate change adaptation, migration, and security. Here we analyze the treaty's migration provision which will enable citizens of Tuvalu to live and work in Australia. We ground our analysis in the state of knowledge about climate change and migration in Tuvalu, explaining the Falepili Union and the ways in which its migration provision may be either a mechanism for adaptation or maladaptation. We then describe a range of policy conditions to maximize the adaptation outcomes for Tuvalu and Tuvaluans. These include measures from the Australian government to support Tuvaluans who migrate as well as the Tuvaluan-Australians who will be key to their integration, and invest in key sectors in Tuvalu such as coastal protection, ICT, and transport. Cooperation between the Tuvalu and Australian governments will also be needed to help direct remittances into public goods and adaptive technologies and practices, to harness the benefits of skills and training for both economies and to monitor the scheme to ensure it delivers adaptation outcomes to Tuvalu and Tuvaluans. Further policy measures discussed include the selection of people eligible for migration and improved communications about the benefits and risks and governance of the scheme. Most if not all of these will be necessary if the migration provision of the Faleplili Union is to be a mechanism for adaptation.