Fish Finder Reviews
Garmin GPSMAP 431S GPS Dual Beam Combo Fishfinder Review

Garmin GPSMAP 431S Review

Garmin 431s: All I can say is this is probably the last review of Garmin Fish finders, I will probably do. You really have to search the Internet to get any kind of Information from this manufacturer. This is a nice unit and Garmin is a good manufacturer of these kinds of products. There are good reviews from owners on this and is one of the reasons I decided to do this review.

Garmin GPSMAP 431S GPS Dual Beam Combo Fish Finder Review

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GPSMAP 431s Features

  • The Garmin 431s is a compact chart plotter that features an ultra-bright 4″ QVGA color display along with an improved high-speed digital design for increased map drawing and panning speeds. It’s ready to go with a built-in, satellite-enhanced base map preloaded with U.S. Inland Lakes and an easy-to-use interface designed to help you navigate the open waters with ease. For areas outside the U.S., the Garmin GPSMAP 431S GPS Dual Beam Combo has a worldwide base map with satellite images in place of more traditional maps.
  • The GPSMAP 431s also accepts BlueChart® g2 Vision® cards for added features and functionality such as high-resolution satellite imagery, 3-D views, and Auto Guidance technology.
  • The GPSMAP 431s also comes standard with a high-sensitivity GPS receiver for superior satellite tracking and quicker acquisition times. And with an SDTM card slot, it’s easy to add additional maps


  • 11.3 x 8.4 x 5.5 inches ; 4.5 pounds
  • Alarms for fish size, shallow water, deep water, and low battery
  • Power output: 400 watts (RMS) 3200 watts (peak to peak), dual beam


  • Tilt & Swivel Mount
  • Simple Controls


  • QVGA display
  • Color Screen
  • The clear screen that shows up well in any light conditions
  • Screen Resolution (VxH) = 240 x 320
  • Ultra-bright 4″ diagonal QVGA display, 240 x 320 pixels – over 800 nits of brightness
  • High-speed processor for fast screen redraws and smooth panning
  • Depth: 900 feet/300 meters (dual beam)
  • UltraScroll high rep rate sonar provides lightning-fast screen updates
  • Water temperature log graphically records water temp data

In the Box

  • Garmin GPSMAP 431S 
  • Tilt/swivel mount
  • Protective front cover
  • Power/data cable
  • Documentation
  • Dual beam transducer

Garmin GPSMAP 431S  Pros & Cons

Garmin 431s Pros

  • Preloaded with charts for over 14,000 U.S. lakes and navigable rivers
  • Waterproof
  • Built-in high-sensitivity GPS receiver
  • With an SD card slot, it’s easy to add additional maps without connecting to a computer

Garmin 431s Cons

  • Transducer wire is 25-30 ft long..Does not tell you this anywhere.
  • Lacks the SD card

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Not a whole lot of things to comment about on this Garmin Fishfinder…Some say it is very easy to Install…

A question asked was will it show the coastal channels and waterways and the answer were The unit has an SD card slot, I recommend the purchase of a Nav Chart for the area that you are operating and you’ll have all the info you need. Out of the box, this is a great little unit for the price, but for serious navigation, get the add-on software maps.