We apply a Lagrangian-based moisture back trajectory method on two reanalysis datasets to determine the moisture sources for wet season precipitation over the Arabian Peninsula, defined as land on the Asian Continent to the south of the Turkish border and west of Iran. For this purpose, we make use of evaporative source region between 65°W–120°E and 30°S–60°N which is divided into twelve sub-regions. Our results indicate a north to south spatiotemporal heterogeneity in the characteristics of dominant moisture sources. In the north, moisture for precipitation is mostly sourced from European land and major water bodies, such as Mediterranean and Caspian Seas. Areas further south dependent on moisture transport from the Western Indian Ocean and parts of the African continent. El Nino Southern Oscillation cycle (ENSO) oscillation exhibits an overall positive but sub-seasonally varying influence on the precipitation variability over the region with mostly positive moisture anomalies form all major source regions. A significant drying trend exists over parts of the Peninsula, which is partly attributed to anomalies in the moisture advection from the Congo Basin and South Atlantic Ocean. However, precipitation trends over the terrestrial part of evaporative source region vary across observations and reanalysis datasets, which warrants the need for additional modeling studies to further our understanding in the identification of key processes contributing to the negative trends.