The data set comprises concentrations of dissolved N2O from seawater samples collected during 16 expeditions to Lake Grevelingen (The Netherlands). The expeditions took place onboard R/V Navicula between the September 2020 and September 2023 and focused on physical and biogeochemical surveys of the area. Samples were collected by drawing water from a 10 L Niskin bottle into borosilicate 100 mL vials, which were then sealed with rubber (butyl) stoppers and aluminium caps. Immediately after collection, samples were preserved by adding 200 µL of a saturated mercuric chloride solution. Samples were analyzed by means of a standard headspace method coupled to gas chromatography/electron capture detection (see e.g. Wilson et al., 2018; https://doi.org/10.5194/bg-15-5891-2018).