Ammonia recovery from wastewater is crucial for mitigating environmental impact and complying with regulatory standards. Therefore, this study aimed to explore the potential of a pilot scale continuous flow crystallizer reactor to recover ammonia from urea fertilizer plant wastewater through struvite crystallization. Based on principles validated in previous batch experiments, continuous flow crystallizer reactor was designed and operated using identified optimal parameters. Reactor was fed with synthetic wastewater containing ammonia concentration of 500-1000 mg/L and operated under varying hydraulic retention times of 3-5 hours. The influent concentration of MgCl2·6H2O and KH2PO4 were adjusted to match ammonia concentration in reactor, maintaining a molar ratio of Mg:NH4:PO4 at 1:1:1, with pH between 9 and 10. The results showed that over 90% of ammonia was removed and recovered as struvite crystals, with a mean size of 0.1 to 1 mm, allowing for effective sedimentation and harvesting. This showed that reactor could potentially handle higher loading and achieve greater removal rates. Furthermore, effluent concentration met the standards set by the Indonesian government for the urea fertilizer sector, specifically for discharge into seawater. The study showed the feasibility of using continuous flow crystallizer reactor for efficient ammonia recovery through struvite crystallization. This method reduced ammonia levels in the effluent, thereby mitigating environmental impact, and produced struvite, which could be used as a slow-release fertilizer to improve economic value. The promising results suggested the potential for further development and industrial application of this method to address environmental and economic challenges associated with ammonia-containing wastewater.