Targeted gene flow is an emerging conservation approach which involves introducing a cohort of individuals with particular traits to locations where they can effect a conservation benefit. This technique is being proposed to adapt recipient populations to a known threat, but questions remain surrounding how best to maximize conservation outcomes during periods of continuous directional environmental change. Here we introduce a new management objective — to keep the recipient population extant and with maximum diversity of local alleles — and we explore how varying the timing and size of a given introduction can maximise this objective. Our results reveal a trade-off between keeping a population extant and maintaining a high level of genetic diversity, but management levers can often optimize this so that nearly 100% of the allelic diversity is preserved. These optimum outcomes sets are highly sensitive to the predicted rate of environmental shift, as well as the level of outbreeding depression in the system.