An underwater glider is a type of autonomous underwater vehicle (AUV) that uses small changes in its buoyancy in conjunction with wings to convert vertical motion to horizontal, and thereby propel itself forward with very low power consumption.

Floats, sometimes referred to as ocean profiling floats, are designed to drift at a fixed pressure and depth. After a certain time period, the floats move upward in the water column collecting profiles of pressure, temperature, and salinity data on their way to the surface. Once at the surface, the floats remain there for under a day, transmitting the data collected by satellite back to NOAA, and thereby allowing one to determine their surface drift. They then sink again, and repeat their mission.