This paper describes the present status of the development of the underwater glider for virtual mooring. It will be able to stay in a designated area for more than one year, moving between the sea surface and the seafloor up to 2,100 m in depth, and monitor the sea environment. It will be able to sleep on the seafloor or while drifting in water to extend the monitoring duration. The first sea-test was conducted in March 2012. In 2013, a new small buoyancy engine was developed and then substituted for the existing one. In recent sea-tests, we evaluated its pitching and heading control performance.