Sea surface temperature (SST) measurements collected by surfers around the southern UK and western Ireland coastline between 2014 and 2017. dataset https://portal.medin.org.uk/portal/start.php?tpc=006_08d93111e4e759bc8def841318859da6 This data collection consists of sea surface temperature (SST) data collected by recreational surfers around the southern UK and Western Ireland coastline over the period from 5th January 2014 to 8th February 2017. These data were collected as part of a research project supported by Plymouth Marine Laboratory. Over the study period, the recreational surfers collected 297 independent samples of SST. The surfers were equipped with a UTBI-001 Tidbit V2 Temperature Data Logger and a Garmin etrex 10 GPS. The Garmin etrex 10 device was used to extract GPS information (latitude and longitude) for each surf. The Tidbit V2 temperature logger was attached, using cable-ties, at mid-point to the leash of the surfboards to ensure continuous contact with seawater when surfing, measuring temperature in the top metre of the water column. Roughly every 6 months over the study period, the Tidbit V2 temperature loggers were rigorously compared with a VWR1620-200 traceable digital thermometer (with an accuracy of 0.05 degrees C at the range of 0 to 100 degrees C) at 1 degree C intervals from 6 to 25 degrees C using a PolyScience temperature bath. Over the study period, all sensors performed within the manufacturers technical specifications. A piecewise regression to model was used to correct any Tidbit V2 temperature data collected to remove systematic biases between sensors, such that the errors in each sensor were within the accuracy of VWR1620-200 traceable digital thermometer. Temperature data were collected at 10 second intervals during each surfing session. The data were processed to remove any data collected before and after entering the water and SST were extracted by computing the median of the remaining data. Standard deviations on the remaining data are also provided to give an index of SST variability during each surf session. 20171003 20170719