Due to the high reliance on fossil fuels in the electricity production and transport sectors, completing the energy transition holds a particular importance for non-interconnected territories. The environmental impacts from electricity generation are mainly imputed to fossil fuel based technologies, for instance in the case of French insular territories. This paper summarizes the present electricity situation in these territories and aims to determine their different emissions and environmental impacts through a life cycle assessment (LCA) approach. To deliver 1 kWh of electricity to the power grid from the studied regions, the electricity mix is defined as the functional unit. The results refer to a life cycle cradle-to-gate electricity production model. The impact categories discussed in this paper are related to global warming potential, acidification potential, tropospheric ozone precursor potential, and the cumulative energy used. Due to its high share of renewable energies sources, French Guyana has the lowest greenhouse gases (GHG) emissions per kilowatt-hour produced compared to the other islands (373 g CO 2-eq/kWh, 4.29 g SO 2-eq/kWh and 2.65 g NMVOC-eq/kWh). Combined with other social, economic and environmental parameters, these results will be also used to determine the typologies of islands in order to define a common energy strategy for each group.