This study proposes a methodology for selecting global climate models (GCMs) from the Coupled Model Intercomparison Project phase 6 (CMIP6) on the basis of their ability to simulate characteristics of mean and extreme precipitation over North-East Africa and Arabia. The seasonal climatology, annual rainfall cycles, and spatial and temporal variability (as documented by five ETCCDI indices) of twenty-five GCMs have been assessed against rain gauge observations and seven gridded rainfall products. Most of the GCMs simulate reasonably well the climatology of mean rainfall (annual and seasonal totals and number of rainy days). Large discrepancies are found in the reference products for some indices related to rainfall intensity (SDII, P95 and R95ptot), which is a major concern for the validation of GCMs. For these indices, we evaluate whether historical CMIP6 simulations fall within the uncertainty range of the rainfall estimates. Ten CMIP6 models are finally retained based on their ability to reproduce the geography and seasonality of mean and extreme rainfall. They tend to have a higher spatial resolution, although there is no systematic relationship between resolution and skill. The selected CMIP6 models perform better, not only at the regional scale (by construction), but also, and more meaningfully, at the local scale of the Republic of Djibouti particularly for the March-to-May rainy season. In a companion paper, the projections of the selected CMIP6 models will be used to study future changes in mean and extreme precipitation over North-East Africa and Arabia.