Cutaneous melanoma and squamous cell carcinoma (cSCC) have different associations with sun exposure, so comparing trends in the incidence rates of the two cancers may offer insight into changing patterns of exposure to ultraviolet (UV) radiation. We compared incidence trends for both cancers in seven susceptible populations living at mid-to-high latitudes: Finland, Norway, Sweden, Denmark, Scotland, the Netherlands and Tasmania (Australia). To describe trends in the age-standardized incidence rates for melanoma and cSCC we fitted Joinpoint models and calculated the average annual percentage rate of change for the period 1989-2020. We calculated the incident rate ratio of cSCC to melanoma and constructed age-period-cohort models. The ratio of cSCC-to-melanoma incidence increased over time, and with proximity to the equator. In 2020, the incidence of cSCC was higher than the incidence of melanoma for men and women in all seven populations. The ratio of cSCC-to-melanoma incidence was higher for men compared with women in all countries; however in most countries, the cSCC-to-melanoma IRR increased over time more markedly in women compared with men. Among younger people, the incidence of melanoma was higher than the incidence of cSCC, and the reverse was true for older people. The age at which the incidence of cSCC overtook incidence of melanoma was strongly correlated with latitude, and was lowest in Tasmania. Our findings confirm the stronger association between age-associated cumulative sun exposure and cSCC compared with melanoma, and suggest that women are receiving greater cumulative UV radiation exposure in recent decades.