One of the largest Constructed Wetlands (CW) for municipal wastewater treatment and reuse has been built in the Kingdom of Saudi Arabia (KSA) along the Red Sea coast. This CW is designed and constructed for the Red Sea Global (RSG) project with a design capacity that will reach of 16,000 m3/day by 2030 corresponding to up to 80,000 inhabitants. The facility is segmented into three construction phases: CP1, CP2 and CP3 each with respective capacities of 6,000, 6,000, and 4000 m3/day. CP1 and half of CP2 have been constructed corresponding half of the total design capacity. The treatment train includes a pre-treatment stage (screening, sand and fat removal) followed by three CW stages: Stage A (VFCW1; Vertical Flow CW), Stage B (VFCW2), and Stage C (HFCW: Horizontal Subsurface Flow CW). Local reed species (Phragmites communis, syn. australis and Cyperus Papyrus) have been planted in the beds. The objective is to provide a Treated Sewage Effluent (TSE) that meets the national 2006-MWE TSE standard for restricted irrigation in KSA and the Minimum Function Specification (MFS) set by RSG. The primary challenge is meeting these standards under the arid and hot climate of the region that induces high evapotranspiration rates. This study reports the first two years of operation during which the maximum inflow exceeded 5000 m3/day. The CW performance was monitored and optimized in order to address issues such as the occasionally high influent TDS values, the challenge to reach the strict effluent TN limit and the gradual increase of the treatment capacity. Overall, the CW managed to reach the TSE standards for landscape irrigation, achieving high average removal rates over the monitoring period of TSS (98.9 %), BOD5 (98.7 %), COD (92.9), ammonia nitrogen (96.1 %), nitrate (97.9 %), total nitrogen (84.9 %) and total phosphorus (76.8 %). The adoption of modifications such as step-feeding with small amounts of raw wastewater to the HFCW inlet combined with TSE recirculation maintained the effluent TN value below the national limit. This large-scale case study demonstrates that CW technology can be an effective sustainable and circular solution for wastewater treatment and reuse even in the most difficult environmental conditions and at the largest scale.