A high percentage of island floras are at risk of extinction and have been reduced to relic populations, often in remote hard-to-reach areas. Uncrewed aircraft systems (UAS aka drones) are now being utilized to assist in the survey and collection of rare plants in inaccessible areas or vertical cliff habitats. Here, we test the application of this technology for conservation of 23 plant taxa in three oceanic island hotspots: Hawaiʻi, Madeira and the Republic of Palau. We collect high-resolution imagery using a small UAS to document the distribution and abundance of vascular flowering plants. Location information is then used to map and assess plant populations. Depending on the terrain, collections are completed using either traditional rope techniques or newly developed remote drone-based collection methods. Over the course of 6 years, we have greatly expanded our knowledge of rare and endangered species, while increasing survey efficiency and staff safety. Most importantly, this work has had a large impact on the conservation of critically endangered plants. Although using drones for botanical conservation comes with limits and challenges, we see great potential in the continued employment of these techniques wherever plants are growing on cliffs or in other hard-to-reach areas.