The increased likelihood of extreme weather events and sea-level rise associated with anthropogenic climate change pose a major flood risk to many coastal regions. Seawater flooding poses not only a serious threat to many already threatened (semi-)natural ecosystems, but also often results in significant socio-economic costs to the many millions of people that now live along the coastal fringes of all major continents. This threat has traditionally been countered by the construction of so-called hard defenses such as concrete walls, a solution that all too often proves to be expensive, inflexible, and of limited value to local biodiversity. Contemporary coastal management now recognizes the need to integrate man-made engineering solutions with natural ecosystems (so-called ’soft-defenses’), or in some cases simply sacrifice areas of low economic value to the sea. Consequently, across the world, many coastal (sand dunes, salt marshes, mangroves) habitats are now recognized for their important contribution to flood defense. Nevertheless, research has only recently focused on ways in which management of these ecosystems might complement or replace ‘hard-structure’ flood defenses. Similarly, while planned flooding is increasingly seen to be a viable option where defense is inappropriate, or where habitat creation forms part of a ‘biodiversity offset’ scheme, only recently have ecologists begun to examine how the recipient community will respond to, and recover from, prolonged seawater immersion. We assemble at ESA 2018 a group of established and early-career ecologists to synthesize and understand these complex issues. Our session will explore new research on how coastal plants and vegetation respond to the flood risk associated with rising sea levels, and an increase in the frequency and severity of extreme events like storm surges. The second half of the session looks at how we can incorporate coastal ecosystems into integrated defense strategies. Speakers include those with expertise in habitat-specific ecology (salt marsh, mangrove, seagrass), factors affecting plant community responses and transitions in accidentally and deliberately flooded sites, large-scale mapping of vegetation response to seawater inundation, and the integration of coastal ecosystems in defense management. By bringing this diversity of topics together, we aim to develop a synthesis between these distinct fields and promote future interdisciplinary research on how land managers might best understand plant community response to flooding and use coastal vegetation as part of an integrated, strategic defense of our threatened coastlines.