Arctic coastlines and corresponding erosion rates as well as natural hazards have been in the focus of research in recent years. While most studies discuss coastal dynamics in ice-rich permafrost, coastal high-Arctic rock walls and their thermal regime are still poorly understood. In this study, we present four years of rock surface temperature (RST) measurements of rock walls in Kongsfjorden, Svalbard, including a comparison between coastal and non-coastal settings. Furthermore, we give insights into one year of RST measurements along the coastline ranging from the inner to the outer part of Kongsfjorden as well as coastal rock walls at the open sea. For evaluation, we applied the surface energy balance model CryoGrid 3, taking into account modified radiative forcing in vertical rock walls. Our measurements show that coastal cliffs are characterized by higher RST than non-coastal rock walls with up to 1.5 °C difference in mean monthly values. The model evaluations indicate that this effect results mainly from (1) higher air temperatures at the coast compared to inland settings and (2) long-wave emission by relatively warm seawater. Ice coverage on the fjord counteracts this effect. Consequently, sea ice loss might lead to higher RST in coastal rock walls during previous periods of sea ice coverage. Calculations of the surface energy balance show that fluxes in coastal and non-coastal settings differ only slightly in summer and fall. However, pronounced differences can be detected in winter and spring, when the water body of the fjord acts as an additional energy source for the coastal settings. We discuss different factors for the thermal regime of high-Arctic rock walls, as well as implications for the erosion of these coastlines in a future warmer climate.