Skip Navigation

Find those fish

Garmin echo 300c

Full-color 3.5" screen

If you want to catch fish, you need to be where the fish are. A Garmin fishfinder will give you a clear, accurate picture of what lies below, so you'll know where to drop your line every time. The rest is up to the fish, of course, but at least you've done your part.

Color coverage to 1500 feet

Garmin's echo 300c fishfinder is a small device designed to help you catch big fish. This Garmin uses HD-ID™ technology and a dual-beam transmitter with 300 watts of sonar power to scan depths of up to 1500 feet in fresh water or 600 feet in salt water.

With a viewing angle of up to 120 degrees, you'll see fish well beyond the sides of your boat, even in shallow water. And whether you're fishing in morning mist or afternoon sun, you'll see every fish arc on the fast-refreshing 3.5" color display.

The echo 300c also features Garmin's Smooth Scaling™ technology, so you won't lose sight of the sonar history as the unit changes depth ranges. It also allows you to rewind your sonar history in order to ensure that you haven't missed a thing.

Hardware included

The echo 300c's compact, portable design makes it the perfect fishfinder if you have a small boat or multiple boats. Plus, its quick-release tilt mount and transducer are easy to install and remove. The tilt/swivel mounting bracket can be installed on your boat's trolling motor or transom.

Product Highlights:

  • 3.5" color display (240 x 320 pixels)
  • accurate to 1500 feet deep in fresh water or 600 feet in salt water
  • 300 watts (RMS) sonar transmitting power
  • dual-beam 200 KHz transmitter
  • beam width to 120 degrees
  • built-in Smooth Scaling technology
  • audible alarm
  • tilt/swivel mount, transducer, trolling motor clamp and transom mount
  • dimensions: 4.1" W x 5.8" H x 2.8" D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Garmin echo 300c Reviews

Hands-on research

What's in the box?

Download owner's manual

  • Fishfinder display
  • Swivel mount
  • 6' Power cable
  • Transducer with 20' attached cable
  • Transducer mounting bracket
  • 20" Cable tie
  • Four 5-1/2" cable ties
  • One 10-32 x 1.75" screw
  • 2 5mm Flat washers
  • Rubber washer
  • 10-32 Nylock nut
  • Cable-entry cover
  • 2 Cable clamps
  • Two 30mm screws
  • Four 12mm M4 screws
  • 2-3/4" x 2" Mount gasket (rubber pad)
  • Owner's Manual (English)
  • Owner's Manual (French)
  • Echo Installation Instructions (English)
  • Echo Installation Instructions (French)
  • Important Safety and Product Information

Product Research


Overview: The Garmin echo 300c is a compact fishfinder designed for small boats. It features a 3.5" QVGA color display and a 300-watt, dual-frequency sonar transducer to help you locate fish in up to 1500 feet of fresh water (600' of salt water).

HD-ID: Garmin's exclusive HD-ID target tracking technology provides enhanced separation and definition of the images on the screen. It shows exceptional structure detail and clear bottom contours. The unit can be set to show suspended targets as sonar "arches" or as a fish symbol with (or without) target depth information.

Display: The echo 300c features a 3.5" (diagonal) QVGA color display with 240 x 320 pixels. The display has a vertical orientation with 3-level backlighting (max, 50%, min). The unit comes with a 3" diameter swiveling base that can tilt from 0° to 90° (7 positions) and lock into place. The display has a selectable color scheme, white or blue, with colors to represent strong, medium, or weak sonar returns. You can also choose a day or night mode for either color scheme.

Transducer: The dual-frequency (200 kHz/77 kHz) transducer transmits sound waves through the water and receives them to relay information to the display. The 200 kHz frequency shows better detail, has a narrower beam (60°) and is typically used in shallower waters. The 77 kHz frequency penetrates deep water more effectively, and has a wider beam (120°), so it can be used to cover a larger area. The transducer has an attached 20' cable to accommodate large or small boats. The transducer can be mounted either to the transom of the boat, or to the bottom of your trolling motor. Mounting hardware for both locations is included.

Viewing Pages: The echo 300c's display scrolls from right to left to show the sonar readings from the transducer. The bottom depth is displayed in large numerals, along with the water temperature, and water speed. The unit has an adjustable depth range (Auto or manual 5' to 1500'), and the depth scale is shown at the bottom of the screen, along with the transducer frequency. You can choose from a full screen page or split pages:

  • Full Screen Page: The Full Screen page shows a full-view graph of the sonar readings from the transducer.
  • Split Zoom Page: The Split Zoom page shows a full-view graph of the sonar readings on the right side of the screen, and a magnified portion of that graph on the left side.
  • Split Frequency Page: The Split Frequency page shows the 77 kHz frequency sonar data, while the right side shows the 200 kHz frequency sonar data.

Flasher Page: The Flasher page shows sonar information on a circular depth scale to indicate what is beneath your boat. Shown in the corners of the page are the voltage, water temperature, water speed, and odometer.

Log Pages: You can view a log of depth readings or water temperature readings on the full screen. Shown in the corners of the page are the current reading, the minimum, and the maximum readings. The depth log and temperature log pages can be shown individually or together on a over/under split screen.

Sonar Rewind: The echo 300c lets you pause and then scroll the screen to view your sonar history.

A-Scope: The A-Scope is a vertical flasher along the right side of the Full Screen page that shows the range to targets in real time along a scale. This view expands the most recently received sonar data so that it is easier to see. It can also be helpful in detecting fish that are located close to the bottom.

Beeper/Alarms: The echo 300c has a beeper that will sound to confirm each button press, or can be set to sound only for alarms, or turned off completely. There are several audible alarms that can be independently set in the menu:

  • Shallow: The unit will alarm when the water depth is shallower that the set value (0 to 999.9').
  • Deep: The unit will alarm when the water depth is deeper than the set value (0 to 999.9')
  • Battery: The unit will alarm when the battery voltage is lower than the set value (9V to 28V)
  • Fish: The unit will alarm when the device detects a suspended target. You can set the alarm for all fish, medium and large fish, or large fish only.
  • Water Temperature: The unit will alarm when the water temperature varies more than +/- 2°F.
  • Drift: The unit will alarm when variations in depth at your present depth location exceed a specified depth.

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Customer Q&A

1 question already asked

We have not received any answers from other customers on your question. I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They should be able to help answer your question. [ Jeff  Mar 05, 2015 ]  Staff