InAs quantum dots grown by molecular-beam epitaxy on GaAs substrates are demonstrated to be suitable structures to achieve an optical emission in the 1.3–1.5-μm range. Their tuning towards such long wavelengths was made possible by combining an extreme reduction of the InAs growth rate and a fast growth of the GaAs cap layer at low temperature. Our results create perspectives for the fabrication of GaAs-based devices operating in the most important telecommunications window.