As one of the lowest-lying island nation states in the world, the Republic of the Marshall Islands is vulnerable to sea level rise, flooding and the associated impacts on soil and water salinity. Persistent drought is further affecting agricultural production and access to drinking water, and heat stress is increasingly common. The number of Marshallese people residing in the USA has increased rapidly from 6650 in 2000 to an estimated 30,000 in 2018. While we know that climate change is already affecting the Marshall Islands and that there are significant migration flows, we do not know to what extent people already migrate because of climate change. This paper addresses this gap and presents findings from interdisciplinary fieldwork in the Marshall Islands and destination areas in the USA. The research team conducted a survey (N = 278), focus group discussions, expert interviews and a geo-spatial analysis of flood extent and migration rates to study the relationship between climatic events, ecosystem services and migration. The results show that respondents primarily cite education, health care, work and family visits as migration drivers, and only few mention climate impacts or environmental change. However, respondents do identify impacts of climate change on their livelihoods, health and safety, and the study finds significant correlations between climate impacts, trends in ecosystem services and migration propensities at household level. Furthermore, 62% of Marshallese respondents in the USA indicated that climate change affects their decision to return to Marshall Islands in the future.