Multistep wafer‐annealed semi‐insulating GaAs wafers (MWA) are characterized using photoluminescence (PL). The PL spectra present well‐resolved near‐band‐edge transitions, including the doublet of the neutral acceptor‐bound exciton. A detailed investigation using selective pair luminescence of samples submitted to different annealings, i.e., wafer‐ or ingot‐annealing, single or multistep, shows that carbon is the main shallow acceptor. However, for the wafer‐annealed samples, two other residual impurities found in the as‐grown or ingot‐annealed crystals have their estimated concentrations noticeably reduced, for Zn (e.g., around 1013 cm−3 in MWA), or are unresolved for Si. This reduction of background impurities may have direct consequences for device applications.