This paper characterised and evaluated the ability of a smartphone camera to measure ultraviolet radiation (UVR) through various types and thicknesses of glass. Image sensor responses from a smartphone with UVA transmitting filters were measurably stronger in the red colour channel than the blue, with the green colour channel responding weakly. Strong correlations of up to R 2 = 0.96 have been determined from calibration of the red and blue channel image responses against measured UVA irradiances for data obtained from both the horizontal plane and the sun-normal plane. For the validation data of the red channel and the blue channel respectively, the mean absolute error was 13.7% and 17.4% for the horizonta l plane and 3.8% to 5.6% for the sun-normal plane. This research has concluded that it is possible to determine UVA irradiances through glass, of different thicknesses, using a smartphone camera with high degree of accuracy.