The diffusion and activation of arsenic implanted into germanium at 40 keV with maximum concentrations below and above the solid solubility (8 × 1019 cm−3) have been studied, both experimentally and theoretically, after excimer laser annealing (λ = 308 nm) in the melting regime with different laser energy densities and single or multiple pulses. Arsenic is observed to diffuse similarly for different fluences with no out-diffusion and no formation of pile-up at the maximum melt depth. The diffusion profiles have been satisfactorily simulated by assuming two diffusivity states of As in the molten Ge and a non-equilibrium segregation at the maximum melt depth. The electrical activation is partial and decreases with increasing the chemical concentration with a saturation of the active concentration at 1 × 1020 cm−3, which represents a new record for the As-doped Ge system.