We report the on the characterisation of 1.3μm emitting GaInNAs quantum well (QW) lasers grown by molecular beam epitaxy using a plasma nitrogen source. Through the optimization of the structural and optical properties as a function of substrate temperature and nitrogen flux conditions, we show that high optical quality structures, which exhibit good room temperature photoluminescence intensity and photoluminescence linewidths <10meV at low temperature, can be routinely achieved. To obtain 1.3μm emission, we employed a structure containing quantum wells with an indium content of 40% and a nitrogen content of 2.5% which have low nitrogen content (1%) lattice matched quaternary GaInNAs barriers, the latter enabling us to grow thick barrier structures without introducing further strain. For unmounted and uncoated 15μm ridge waveguide lasers we have achieved threshold current densities as low as 377Acm-2 for a 3 QW and record low value of 178Acm-2 for a single QW device emitting above 1310nm. The devices show excellent temperature characteristics with characteristic temperatures >90°C observed in several structures. In comparison to GaInAs quantum well lasers, the results show that at this composition (2.5%) there is no appreciable degradation of performance due to the presence of nitrogen in these samples. Increasing the nitrogen content by 1% was observed to shift the wavelength to 1390nm, but with a threshold current density increased by a factor of 2 to 830Acm-2. The results also indicate that although high quality GaInNAs lasers can be achieved at wavelengths suitable for the 1.31μm optical fibre waveband, the performance of devices with higher N content, and therefore with emission at longer wavelength, are degraded.