Seaweed has historically been essential for coastal communities worldwide. Following a period of decline in the last century, Ireland has seen a recent resurgence in the appreciation and use of seaweed. This research explores the evolution in seaweed foraging practices, with a specific focus on gastronomical uses in two Irish regions: the southwest and the west and midwest. It examines the diversity of seaweed and its present and past uses, comparing abandonment, continuation and revitalisation trajectories. Qualitative data were gathered through semi-structured interviews with 27 individuals who forage seaweed for commercial or personal use. We identified 22 seaweed species across the study areas, predominantly from the Fucaceae, Laminariaceae and Ulvaceae families. There was a fair divergence between the seaweed species used in the two study areas (16 seaweed species in the southwest region and 17 seaweed species in the west and midwest region), with 11 species mentioned in both areas. Different trajectories of resurgence were identified. In the west and midwest region, the revitalisation of local ecological and gastronomic knowledge related to seaweeds seems to be deeply entrenched in the territory’s historical legacy, showing a sort of continuation with the past and having followed a more commercially oriented path. Conversely, in the southwest region, the revival seems to be fostered by new knowledge holders with a contemporary interest in reconnecting with the marine landscape and promoting educational activities centred around seaweed. This research contributes to discussions on sustainable food systems and food heritage promotion, emphasising seaweed’s potential role in Irish coastal communities’ foodscapes.