This dataset contains a mosquito species table with counts for adults and larvae. Samples are from twelve UK wetland sites, sampled between April 2017 and September 2018. A map included in the documentation included with this data shows site locations, which include both coastal and inland wetlands, and range from Devon to Kent and from Lincolnshire to Dorset. Samples were collected by staff from University of Greenwich and the UK Health Security Agency: collaborators in a NERC-funded project (NE/NO13379/1), part of the Valuing Nature Programme. We found a total of 19 mosquito species: • 10 Aedes • 3 Anopheles • 3 Culisseta • 2 Culex • 1 Coquillettidia.