An overlay network can be extended to edge routers for a substrate network. A request to make an overlay network available may be received at a network manager for a substrate network. The network manager may update an edge router to add an overlay network route to the edge router. The edge router can then indicate that the network route is available for handling network traffic. When network traffic directed to the overlay network is received at the network route, the edge router can forward the network traffic to the overlay network according to the added network route.