In a very near future Wireless LANs and UMTS technologies will have to co-exist in many populated areas. Since UMTS radio cells are more limited in capacity than WLANs Access Point (APs), this technology integration gives operators the opportunity to perform inter-network load balancing by transferring services to WLANs hotspots. By doing so, UMTS cell congestion can be alleviated and capacity can be freed for future real time connections. Several scenarios arise depending on the level of congestion of both networks. This research studies such scenarios by assessing the impact of performing inter-network load balancing when transferring non-real time traffic. Promising results show how light and intermediate loaded neighboring WLANs hotspots can absorb up to 50% of the load of a congested UMTS cell, enhancing the throughputfor switched non-real time applications andfreeing 50% capacity offorfuture real time UMTS calls. This is achieved without degrading the service of existing applications in the WLAN hotspot.