Category Archives: Garmin GPSMAP 421s

Garmin GPSMAP 421s vs 431s

A product comparison between Garmin GPSMAP 421s and 431s Fishfinder/GPS Combos. Comparing differences and similarities between the two Garmin.

Note: This comparison by GPSCompared is a basic guide based on published specifications and features at Garmin official website. And by no means that this comparison is definitive. There might be other similarities and differences which are not covered here.

Garmin Fishfinder/GPS Combos
Garmin GPSMAP 421sGarmin GPSMAP 431s
ModelsGarmin GPSMAP 421s
Garmin GPSMAP 421s
Garmin GPSMAP 431s
Garmin GPSMAP 431s
Introduction DateGPSMAP 421s model was announced by Garmin’s on July 8, 2009GPSMAP 431s model was announced by Garmin’s on July 8, 2009
View the product availability and current price from AmazonGarmin GPSMAP 421s 4-Inch Waterproof Marine GPS and Chartplotter with SounderGarmin GPSMAP 431S GPS Dual Beam Combo
What's Difference
Antenna:Internal with external connectionInternal only
Preloaded maps:NoneInland Lakes (inland maps)
NMEA 2000® compatible:YesNo
SiriusXM™ Weather & Radio compatible:YesNo
Dual-frequency (50/200 kHz) sonar capable:YesNo
Dual-beam (77/200 kHz) sonar capable :NoYes
Frequencies supported:50/200 kHz77/200 kHz
Maximum depth:1,500 ft.
(depth capacity is dependent on water bottom type and other water conditions)
900 ft.
(depth capacity is dependent on water bottom type and other water conditions)
What's Common
Physical dimensions:5.7" x 5.0" x 2.7" (14.5 x 12.7 x 6.9 cm)5.7" x 5.0" x 2.7" (14.5 x 12.7 x 6.9 cm)
Display size, WxH:2.4" x 3.2"; 4.0" diagonal
(6.1 x 8.1 cm; 10.2 cm diagonal)
2.4" x 3.2"; 4.0" diagonal
(6.1 x 8.1 cm; 10.2 cm diagonal)
Display resolution, WxH:240 x 320 pixels240 x 320 pixels
Display type:QVGA displayQVGA display
Weight:1.3 lbs (590 g)1.3 lbs (590 g)
Water rating:IPX7IPX7
Receiver:High sensitivityHigh sensitivity
Mounting options:Bail with swivel or flushBail with swivel or flush
Power consumption:Max power usage at 13.8 Vdc: 15 W
Typical current draw at 12 Vdc: 0.6 A
Max power usage at 13.8 Vdc: 15 W
Typical current draw at 12 Vdc: 0.6 A
Accepts data cards:1 SD™ card1 SD™ card
Waypoints:30003000
Routes:100100
Track log:10,000 points; 50 saved tracks10,000 points; 50 saved tracks
Garmin Sonar compatible:YesYes
NMEA 0183 compatible:YesYes
Supports AIS (tracks target ships position):YesYes
Supports DSC (displays position data from DSC-capable VHF radio):YesYes
Tide tables:YesYes
Transmit power:500 W RMS500 W RMS
Voltage range:10-32 Vdc input10-32 Vdc input
Bottom lock (shows return from the bottom up):YesYes
Water temperature log and graph:YesYes
NMEA 0183 input ports:22
NMEA 0183 output ports:22
What's Unavailable
Garmin Radar compatible:NoNo
Garmin Marine Network™ compatible:NoNo
Garmin SmartMode compatible (customizable monitor presets):NoNo
Garmin Meteor Audio System compatible:NoNo
Supports Fusion Lync compatible marine radios:NoNo
GSD™ Black Box sonar support:NoNo
GCV™ Black Box sonar support:NoNo
BlueChart® Mobile (planning) compatible:NoNo
Garmin Helm compatible:NoNo
GRID™ (Garmin Remote Input Device) compatible:NoNo
Wireless remote compatible:NoNo
Wireless mouse compatible:NoNo
CHIRP sonar technology:NoNo
DownVü™:NoNo
SideVü™:NoNo
Sonar recording:NoNo
Sonar history rewind:NoNo
Video input ports:NoneNone
Video output ports:NoneNone
Wireless connectivity:NoNo
Garmin Marine Network™ ports:NoneNone
Official Specs and Features
Learn more from the manufacturer site.Read more about Garmin GPSMAP 421s at garmin.comRead more about Garmin GPSMAP 431s at garmin.com
Amazon Customer Reviews
inclusive of the most helpful favorable review and the most helpful critical review (if available)
Click here to read the reviews on Garmin GPSMAP 421sClick here to read the reviews on Garmin GPSMAP 431s
Note: Amazon tend to group a few models into one section of customer reviews (i.e models that belong to same series). So when you read a review, do look at which model the review refers to.
Demo Video
Relevant video found at YouTube.comNANA
Check Price
View the product availability and current price from AmazonClick on this link Garmin GPSMAP 421s 4-Inch Waterproof Marine GPS and Chartplotter with SounderClick on this link Garmin GPSMAP 431S GPS Dual Beam Combo

Disclaimer: Information provided is believed correct and true to the best of our ability, however, GPS Compared is not responsible for typographical errors or incorrect data. To report any errors, please contact GPSCompared or visit the official Garmin product page for details specifications.