Castable sonar pairs a small floating transducer with your phone — no console, no battery box, no drilling. It is the simplest way to add sonar to a kayak or fish from shore. The Deeper PRO+ and Garmin Striker Cast lead; both add GPS mapping.
At a glance
The picks
1. Garmin Striker Cast GPS
A castable sonar that pairs to your phone — no console, no battery box, no drilling. The GPS version maps depth contours as you cast, which makes it ideal for tight or minimalist kayak setups and shore days.
2. Deeper PRO+ 2
The castable kayakers actually swear by. Three-beam sonar and a high-precision internal GPS build real bathymetric maps from the deck or shore, with about nine hours of battery and zero mounting.
What to look for
The GPS models build depth-contour maps as you cast — a big step up from a plain sonar ball. Get the GPS variant if it is offered.
Look for 8+ hours of battery and 100+ feet of casting range so it keeps up with a full day and long shore casts.
There is no dedicated screen — you read everything on your phone. Bring a mount and a way to keep your phone charged and dry.
Frequently asked questions
Yes — they are popular with kayakers precisely because they need no mounting or battery box. You cast the sonar ball, read depth and fish on your phone, and stow it in a pocket. The trade-off is phone dependence and slightly less detail than a mounted transducer.
The Deeper PRO+ 2 offers three sonar beams and strong mapping; the Garmin Striker Cast is a bit cheaper and integrates with Garmin’s app and Quickdraw contours. Both are excellent — choose by app preference and whether you want the GPS mapping version.
Yes. You can troll it alongside the kayak on a short line to scan as you move, or cast and retrieve it to map an area. Just mind your line and keep the transducer clear of your paddle stroke.
How we chose
Every spec here is pulled from the manufacturer or an authorized retailer and standardized. We rank transparently and never for commission. Full methodology →