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Raingardens offer a sustainable and nature-based approach to stormwater management and runoff control that provide multiple additional benefits to biodiversity, ecosystem services, and amenity, to name only a few. Raingardens vary in design and can be incorporated into a wide variety of urban landscapes, offering flexibility appropriate for the setting. The aim of this paper is to examine the hydrological performance and functionality of a raingarden installed in Edinburgh, Scotland over a prolonged period. Key characteristics of the raingarden are assessed and compared against the design. The raingarden was designed with two engineered soils: Engineered Soil 1 (retaining 30% existing soil–as recommended by the United Kingdom SuDs Manual) and Engineered Soil 2 (retaining 45% existing soil). We found that despite matching the recommended soil composition, the particle size distribution of Engineered Soil 1 showed variation from that recommended by the Manual. The key soil characteristics of bulk density, porosity, and saturated hydraulic conductivity correlated with the literature for both engineered soils and the existing soil. Whilst Engineered Soil 1 performed best in terms of its ability to intercept and drain runoff (having the highest saturated hydraulic conductivity, with fewer surface ponding events, and lowest retained soil moisture) it had lower soil storage capacity and plant available water than Engineered Soil 2. We also found distinct seasonal differences in infiltration performance in both engineered soils, with summer infiltration of Engineered Soil 1 being 2.5 times that of winter infiltration, and for Engineered Soil 2, summer infiltration was more than 1.4 times that of winter infiltration. Surface ponding in the raingarden was also found to be influenced by the season, with half of all ponding events occurring in winter when water uptake is reduced due to plants being dormant, and evapotranspiration is negligible. All ponding events de-watered within the recommended 48 h. Overall, the raingarden has been shown to retain 100% of runoff. The findings of this study provide helpful insight into key raingarden characteristics and functionality compared to design intent and should prove useful in informing future raingarden planning and implementation.