Fish Finder Tech

Deeper Sonar Pro Plus 2

Overall Rating

Fish finders are incredible tools, but most of them aren’t built for anglers who prefer to do their fishing from the shore or from small vessels like kayaks.

Castable fish finders are designed to solve this problem. They’re small, waterproof, and don’t require any complex setup. Your phone becomes the control head, and through Wi-Fi or Bluetooth, you connect to your castable finder—no complex tethering required.

We’re giving you all of this preamble because today, we’re reviewing what we consider to be one of the best castable fish finders on the market today: Deeper Pro+ 2 Castable Sonar. We’re going to delve into all of the features this unit has to offer—but before we do, here are the pros and cons:


  • Excellent casting range
  • Affordable
  • Great battery life and charge time
  • Good range of supported frequencies
  • Light and portable


  • No CHIRP
  • Lacks the power of non-castable sonar

Technical Specifications

FrequencyNarrow: 675 kHz (cone angle 7°), Medium: 240 kHz (cone angle 20°)
Transmit PowerN/A
Screen SizeN/A
GPSInternal, High-Precision
Maps IncludedGlobal bathymetric maps
Max WaypointsN/A
Memory Card SlotsN/A

Display and Interface

Let’s start with the display. Displays are always funny to talk about when reviewing a castable because the quality of the display depends entirely on the quality of your phone or tablet. Have the newest iPad at your disposal? You’re going to have a bright, clear, big display that will make catching fish that much easier. Have an old Android you bought from a second-hand shop? Things might not be so clear.

Generally, we’d recommend taking a middle-of-the-road device along with you—something that’s got a display that’s big and clear enough to use Deeper’s app but nothing so valuable that you would cry about losing it if you dropped it in the water.

On that note, you do have to install the Fish Deeper app in order to use the device. Fortunately, the app is easy to install, and it’s easy to connect your phone to your device via Wi-Fi.

One handy “display” related feature on the unit is the use of split screens. You can simultaneously view a chart of the area you're fishing and your sonar chart—pretty handy and a somewhat surprising feature from such a small, affordable device.

When it comes to the interface, the Fish Deeper app is quite easy to use. It’s a huge upgrade over the previous app that Deeper had released. The menus are well-laid out and easy to access, and it’s simple to navigate between different sonar split screens and other features like weather. We’re really impressed with the improvements they’ve made.

The unit is plug-and-play; you’ll be able to toss your Deeper Sonar Pro+ 2 into the water, and it will automatically start up. Connect it to your phone via Wi-Fi (following the login instructions included in the manual), and you’ll get images of what’s happening underwater almost right away.

As we’ll discuss in the sonar section, the limited number of sonar screens leads to a particularly well-laid-out menu to swap between different sonar functions. The sonar is absolutely the focus of this unit, though you’ll have access to weather, settings, and a few other neat features we’ll talk about in later sections through Fish Deeper’s menu.

Speaking of Wi-Fi, let’s talk about connectivity (an essential part of the interface) for a moment. The best way to ensure that you’ve got a stable connection is to turn off all connections except for Wi-Fi on the device you’re connecting to the Sonar Pro+ 2 (though you’ll want to keep a stable Internet connection, as well). The range of the unit's Wi-Fi is 330 feet, but you’ll find that this is only true under ideal conditions. We recommend casting it around 200 to 250 feet out, then testing to ensure that your connection is reliable. From there, you can try casting it out further.

All in all, we’re not blown away by the interface—but we’re happy to report the Pro+ 2 is easy to connect to via the app, and the “turns on when it’s in the water” feature is lovely. We expect the Fish Deeper app to improve as Deeper develops its UX and UI capabilities—all in all, it’s a solid, if unimpressive, effort.


We always split our sonar reviews into two sections: One where we talk about the technology underlying the sonar and another where we talk about the actual charts available on the unit. This review is no different!

The Deeper Pro+ 2 has remarkably good sonar for its size. You can switch between three different frequencies:

  • Narrow 675 kHz (cone angle 7°)
  • Medium 240 kHz (cone angle 20°)
  • Wide 100 kHz (cone angle 47°)

675 kHz is quite powerful and gives the greatest level of clarity. 100 kHz, on the other hand, gives the best depth penetration and the widest angle. Our recommendation? Switch between the wide, medium, and narrow options as you scout for fish. Start with a wide cone, then move toward the narrow cone as you find the perfect fishing spot.

The only miss here is the lack of CHIRP, a sonar technology that leads to better target separation and more accurate readings. As we mentioned, this technology is available on the Pro+ 2’s cousin—for about twice the price. Aside from the lack of CHIRP, the sonar is quite good—among the best we’ve seen in castable units.

Let’s talk about the sonar chart. There’s a lot to absolutely love about what Deeper has to offer here. Those of you who have already used Deeper sonars in the past might have been disappointed in the sonar options available. Fortunately, it has upgraded its app to a new model called Fish Deeper—and it’s a whole lot better.

For starters, you’ve got options when it comes to charts! Traditional sonar chart? You got it. Flasher for ice fishing? That’s available, too. Fish icons to make it easier to read the chart—especially for beginners? Yup. You’ve got pinch-to-zoom, you’ve got adjustable sensitivity; all the core features you want from a fish finder are here. There are even a few different color palettes to choose from—something that was sadly lacking from the original Deeper app.

You can even split-screen your sonar chart with your flasher or with your chart (which we’ll talk about in the Mapping section). It’s easy to flip through different sonar frequencies and get a good look at what’s happening below the surface. There’s even imaging—well, kind of (not really)—but we’ll save that goodness for the next section.

One of the best parts of the unit is how well laid out the menus are. Fish finding is clearly the focus of the Fish Deeper app, and on the main screen, you’ll be able to quickly toggle sensitivity, fish icons, the type of sonar you’re using, and more. This app is remarkably intuitive—it’s one of the better user interfaces we’ve experienced on a fish finder. That may be because it’s lacking some of the features you’d see in a more robust fish finder/chartplotter combo, but we’re impressed anyway.

All in all, the sonar for the Deeper Pro+ 2 gets very high marks from us—it’s pretty unbelievable that we can have sonar this good in a device this small.


You might be surprised to see this section. Imaging on a unit this small and affordable? It couldn’t be true, could it?

Well, to be honest—it’s not. Not really, anyway. We just like keeping as standard a format as possible for all our fish finder reviews.

There are, however, images—which counts for enough that we kept this section. You can toggle your sonar from “Basic”, which only provides bottom contour and fish icons, to “Raw”, which provides the full sonar reading. Basic is a good way for beginners to get started on their fish-finding adventure—for everyone else, Raw is absolutely the way to go—and the way to get the best results out of your fishing.

For imaging, we give the team at Deeper N/A out of 5. There’s no real imaging on this device (not that we were expecting it at this size or price point).


You wouldn’t expect many mapping features from a small castable unit—you might not expect any mapping at all! Even if you did expect mapping, you might suspect that it would only work with your phone’s GPS, which could lead to inaccuracies.

You might, then, be as surprised as we were to learn that the Pro+ 2 has its own internal, high-precision GPS. How the team at Deeper managed to fit the tech for GPS and fish finding into a unit this small and light, we’ll never know. What we do know, however, is that they put both to excellent use.

First, you’ll be happy to know that the app comes with a map—not a bathymetric chart (we’ll get to those later), but a simple map you can use to track your location. That’s perfect for setting waypoints so you can go back to the fishing spots you’ve had the most success in. Whether you’re shore fishing, kayak fishing, or anything else, this is an incredibly handy feature to have.

The fun doesn’t stop there, though. That’s right, our favorite pet feature is here—the ability to make your own bathymetric charts. By using the transducer in conjunction with the GPS, your Deeper Sonar Pro+ 2 will build depth charts and overlay them on the map. You can save these charts to plan your future fishing routes. We can’t stress how useful this is;  you can change where you fish depending on seasonal migrations by picking areas with drop-offs, soft bottoms, and other features. Depth charts are all the rage, and we love making our own.

Not everyone wants to make their own charts, though—having a pre-made one can mean getting to the best fishing spots faster. Pre-made charts can also have more accurate readings. Fish Deeper Premium gives you access to high-quality, pre-made charts. There’s an extra charge for the service, but the Deeper Pro+ 2 comes with a free 3-month subscription. We recommend trying it out; if you like it, you can keep the service, and if you don’t, you can move to making your own charts.

By double-tapping on the map at any time, you can add icons to indicate places of interest—or great catches! You can edit this info to create more complete maps—and to brag to your friends about the great fishing spot you found.

The maps have a handy layers feature that allows you to display or remove information like icons from your maps. This is a pretty useful tool—you can really get rid of clutter and focus in on the points of the map you’re interested in.

We’re very impressed with the charting functions on this unit. While it lacks some features (like making your own routes), the charts are solid. We also love that you can look at the map in a split-screen view with your sonar. Keep up the good work, Deeper!


When it comes to networking, there’s not a lot to talk about. You’re not going to connect your Deeper Pro+ 2 to a bunch of other Deeper devices. That said, there are a few things that we need to address.

First off, the Wi-Fi is incredible—330 feet is close to the best we’ve ever seen in a castable (with the Pro+ 2’s cousin, the Deeper CHIRP 2, beating it out once again). One important thing to know: If you’re using an Android device, Smart Network Switch may be active, which can cause your phone to switch off of Deeper’s network. Disable Smart Network Switch if it’s available on your device.

While we’re on the topic of Android, let’s talk about compatible devices. Pretty straightforward: you’ll need a device with iOS 14.0 and later or Android 8.0 (Oreo) and later.

Finally, it’s worth knowing that you can use Fish Deeper on your PC as well as across your devices, all with one account. You can plan your fishing trip from the comfort of your home, and the data will be right there on the app when you’re out on the water. Pretty great stuff!

Other Features

The Deeper Sonar Pro+ 2 comes full of additional features. Here are a few that stand out for us:

  • Night fishing mode, which activates the LED light inside your Pro+ 2. You obviously don’t want to lose track of your fish finder while you’re fishing; this makes it easy to see in even the darkest of waters.
  • Depth alarms that ping when the water column your fish finder is in has reached a certain depth.
  • A show distance to sonar option that tells you how far from your phone or tablet your Pro+ 2 is.
  • A power saving mode

Another feature we want to highlight is the History mode. You can scroll through your sonar’s historical data by simply swiping left (and then right, to move back toward the present). The app also records data from past fishing trips, so you can look through historical sonar readings to get a better understanding of what went right (and wrong) on your past fishing trips. You can upload this data to the cloud and view it from any of your Fish Deeper devices.

The Bottom Line

We absolutely love the Deeper Sonar Pro+ 2. You’re getting incredible value for your dollar—the unit is chock full of features. The upgraded Fish Deeper app is miles ahead of the old Deeper app, with improvements across the board to UI, functionality, and more.

You can use the Pro+ 2 from your kayak, from shore, or basically anywhere you wouldn’t want to use a traditional fish finder. It’s a great beginner model, too—and you can even use it instead of a traditional fish finder if you want a very affordable option.

Outside of the lack of CHIRP sonar and powerful options like imaging, the unit is practically flawless. The Wi-Fi is stable, the casting range is excellent, and it offers a depth range that provides more than enough coverage for most anglers. You’re even getting maps and historical data; that’s a lot of utility in such a small package!

This unit gets extremely high marks from us—it and its cousin, the Deeper CHIRP 2, are tied as our favorite castable sonars on the market. Looking for an affordable, powerful castable? Get this unit.

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