Real-time location and route guidance are essential to support the requirements of accessible travelers. As a part of the USDOT’s Accessible Transportation Technologies Research Initiative (ATTRI), researchers developed a Smart Wayfinding and Navigation (SWaN) service, intended for venue owners and developers to better deliver accessible real-time location, navigation and planning capabilities to travelers. A SWaN service allows a user to navigate independently through complex urban transport structures and continue all the way to their destination. The SWaN mobile service, a background application on standard smartphones, used data from small accessory sensors to estimate the user’s location as they move through a building. The background mobile service with open application programming interface (API) delivered routing, user location, orientation, waypoint navigation, and real-time route guidance within complex transit facilities or public buildings. Field testing and validation of the SWaN capability was conducted at Federal Highway Administration (FHWA) Turner-Fairbank Highway Research Center in McLean, Virginia, Washington Metrorail, and Union Station in Washington, D.C.