The ATLAS experiment is currently upgrading the first muon station in the high-rapidity region with the construction of new detector structures, named New Small Wheels (NSW), based on large-size multi-gap resistive strips Micromegas technology and small-strip Thin Gap Chambers (sTGC). The NSW system will be installed in the ATLAS underground cavern during the LHC long shutdown 2 to enter in operation for Run3. The construction of Micromegas and sTGC detectors is completed at the construction sites distributed all around the world. At CERN, the final validation and integration of the modules in sectors composing the wheel is well advanced, as well as the installation on the final structure and the commissioning on surface. In this presentation the motivation of the NSW upgrade and the current status of the project will be reviewed, with particular focus on the main challenges and the measured performance of the system.