Data are presented describing the operation of single-transverse, single-longitudinal mode strained-layer InGaAs laser diodes operating at λ = 980 nm. These diodes exhibit single-transverse mode behaviour to beyond 210 mW continuous wave (CW) and single-longitudinal mode behaviour to beyond 150 mW CW. The maximum output power is approximately 350 mW CW. The threshold current of these lasers is ∼ 10 mA, with a differential quantum efficiency of 85%. The total efficiency of these diodes exceeds 50% at an output power of 100 mW.