Everything you need to know before buying an SD card.
One of the most common questions we get asked at Wild Coast Kayaks is:
"What is the biggest SD card I can use in my fish finder?"
The answer isn't always as straightforward as you might think. While larger SD cards are widely available today, not every fish finder is designed to use them. In fact, using an incompatible SD card can lead to your unit not recognising the card, software update failures, sonar logging issues or chart cards not loading correctly.
Here's what you need to know.
Garmin Fish Finders
Garmin has gradually increased SD card compatibility over the years, particularly on its latest chartplotter range.
Older Garmin Units
Most older Garmin fish finders and chartplotters support:
- Maximum SD card size: 32 GB
- File system: FAT32
- Card type: SDHC
This includes many older:
- echoMAP
- GPSMAP
- GPS/Fishfinder combinations
New Garmin Models
Many of Garmin's latest chartplotters now support much larger SDXC cards.
Examples include:
- GPSMAP 9000 Series
- GPSMAP x3 Series
- ECHOMAP Ultra
- ECHOMAP Ultra 2
- ECHOMAP UHD2
These newer models can support up to 1 TB SD cards when running current software and using the exFAT file system.
Garmin STRIKER Series
Most Garmin STRIKER models do not include an SD card slot.
This means you cannot:
- Save sonar logs
- Install mapping cards
- Perform software updates via SD card
- Export waypoints to an SD card
Always check the specifications of your particular STRIKER model.
Lowrance Fish Finders
Lowrance has generally remained more conservative with SD card compatibility.
Although larger SD cards may sometimes work, Lowrance officially recommends using cards up to 32 GB for most of its fish finders.
Supported Lowrance Series
The following ranges are best used with:
- Maximum SD card size: 32 GB
- File system: FAT32
- Card type: SDHC
Including:
- HDS Gen1
- HDS Gen2
- HDS Gen3
- HDS Carbon
- HDS Live
- HDS PRO
- Elite Ti
- Elite Ti2
- Elite FS
- HOOK²
- HOOK Reveal
- Eagle Series
Why Doesn't Bigger Mean Better?
Many anglers assume buying the largest SD card available is the best option.
In reality, that's rarely the case.
A quality 32 GB SD card is more than sufficient for:
- Software updates
- Waypoint backups
- Recording sonar logs
- Genesis Live mapping
- Quickdraw Contours (Garmin)
- C-MAP and Navionics charts
In fact, a 32 GB card can store many hours of sonar recordings, making it more than adequate for almost every recreational angler.
Recommended SD Card Specifications
Regardless of whether you own Garmin or Lowrance equipment, we recommend purchasing:
- 32 GB SDHC
- Class 10
- FAT32 formatted
- Buy from a reputable brand
Recommended brands include:
- SanDisk Extreme
- Samsung PRO Plus
- Kingston Canvas Go!
Avoid very cheap, unbranded SD cards, as these are one of the leading causes of corrupted sonar recordings and failed software updates.
Our Recommendation
If you own multiple fish finders, using the same SD card size across all your units makes life much easier.
For the vast majority of Garmin and Lowrance users, we recommend:
✅ 32 GB SDHC Class 10
It offers the best balance of compatibility, reliability and storage capacity.
Only consider larger SD cards if your specific Garmin chartplotter officially supports SDXC cards and you genuinely require the additional storage.
Final Thoughts
Choosing the correct SD card is one of those small decisions that can save a lot of frustration on the water.
Whether you're updating software, recording sonar, creating custom maps or backing up valuable waypoints, a reliable, correctly formatted SD card ensures your fish finder performs exactly as it should.
If you're unsure which SD card is right for your Garmin or Lowrance fish finder, feel free to contact the team at Wild Coast Kayaks. We're always happy to help you choose the right option for your specific unit.
For more information and advice on this topic above, feel free to contact Brett HERE.
