In this paper we present the results of the online pseudo-dynamic network testing using the Internet that were jointly conducted by several institutions in Korea and Japan. Example studies were performed on base-isolated bridges with four continuous spans. Test facilities located at several institutions were interactively used to test the nonlinear behaviors of the base isolators. At first, a series of international network tests was carried out between Japan and Korea, and the performance of two system configurations with different data communication schemes was compared. Then, network tests were repeated on a similar bridge structure between two institutions in Korea, and the overall performance was discussed. A web-based Java monitoring system was developed for checking the partners' testing conditions and for sharing the test results with the authorized observers. Wireless Internet technology using mobile phones was also investigated. The results indicate that the time to execute a single step varies widely, depending on the data communication/sharing schemes and the testing hardware, e.g., 0.2-15 s for data communication and 1-10 s for execution of the pseudo-dynamic tests for each time-step. The time required additionally for data communication in the on-line network testing is judged as reasonable in comparison with the time for the pseudo-dynamic test. The results also show that the wireless communication is very attractive for on-line network testing, owing to the mobility and Internet security.