Suitable for both freshwater and saltwater applications, the Fishfinder 320C has a 16 color high-resolution, sunlight readable screen with 234 x 320 pixels. The Fishfinder 320C is compatible with GARMIN's line of dual and single frequency transducers. GARMIN's colour fishfinder includes features such as bottom-lock which maintains a constant view within a specified depth of the bottom, water temperature recording with graph and GARMIN's exclusive Depth Control Gain (DCG), which adjusts sounder sensitivity by depth, resulting in a more detailed picture of bottom structure.

The Fishfinder 320C can also be used as a GPS repeater, since it has a NMEA 0183 input/output. Angers will have the ability to select data on numeric fields and view their track and bearing graphically and numerically. When linked to a Garmin GPS unit, anglers can use the remote waypoint-marking feature on the Fishfinder 320C to send a specific location to the GPS.