Seaglider is a deep-diving unmanned underwater vehicle (UUV) developed by the University of Washington's Applied Physics Laboratory (APL) as an oceanographic data collection device for long duration missions.

In the summer of 2004, over the course of 25 days, a Seaglider completed 374 successful profiles over 170 horizontal miles  during Rim of the Pacific Exercise (RIMPAC-04).  The Office of Naval Research (ONR) sponsored a Seaglider's participation in a Navy Anti-submarine Warfare exercise in October 2004 called TASWEX-04 in the East China Sea. 

In 2010, Seaglider's manufacturer, iRobot, received two contracts from the Naval Oceanographic Office at the Stennis Space Center in Mississippi.

The Seaglider has been considered for inclusion in the Navy's Persistent Littoral Undersea Surveillance Network (PLUSNet). As currently envisioned, PLUSNet will consist of five Seagliders and six REMUS 600 UUVs.

U.S. Navy sailors were first trained on the Seaglider in the summer of 2013.  

iRobot Seaglider promotional video.

See also:

Autonomous Submarine Drones: Cheap, Endless Patrolling

China's gliders: Haiyan & Sea Wing

LBS Glider