To quickly jump to a section of this review, click the links below:
- Pool Swimming
- Open Water Swimming
- Garmin Connect IQ Apps
- Analysing Swim Data
- Heart Rate Data
- Amazon Links
The Garmin Forerunner 235 is far from designed for swimming; it is instead a mid-level GPS running watch, best used for running and cycling.
However, almost all new fitness watches are waterproof, usually between 30-50m. The Forerunner 235 is rated up to a depth of 50m. This means that it is perfectly protected to be used when swimming, or any other water based activity.
Here I look at how well the Garmin Forerunner 235 is suited to swimming.
The Garmin Forerunner 235 has no specific ‘Swim’ sport mode. Other swimming orientated watches have a specific sport mode which will track more detailed swim metrics such as stroke rate and efficiency. These are available on Garmin’s other watches like the Garmin Swim and fenix 5 below.
When swimming in open water, the watch can use the GPS capabilities and track your distance. However, most likely, you will be swimming indoors in a lapped pool, therefore the GPS function will not work.
With no ‘Swim’ sport mode, the best way to record swimming on the Forerunner 235 is with the ‘Other’ sport mode. This can be used for any type of activity and can record all metrics offered on the Forerunner 235 including Heart Rate and GPS tracking.
It is best to configure the ‘Other’ sport mode to record indoor pool swimming in clear and useful way. To configure the settings for swimming, scroll to ‘Activity Settings.’
Firstly, make sure that GPS is turned to off. This will ensure that the watch doesn’t try tracking your activity – although it is unlikely the watch will connect to GPS from indoors.
Next, I find it useful to have specific data screens available for swimming. The two best metrics that I like to be able to see whilst swimming are cumulative time and the number of laps. You can set these two data fields to be on individual screens or have both on the same screen.
Whilst the watch is unable to detect when you have completed a lap in the pool – other watches like the TomTom Spark 3 do this which I tested here – you can press the bottom-right button to create your own lap. This is not the easiest manoeuvre as you have to break your stroke pattern to reach to your opposite wrist, however it doesn’t cause too many problems.
This is why I find it useful to have a data screen displaying the total number of laps for the activity. The number of laps is representative of the total number of lengths completed. The watch will also display the lap (length) time once the lap button is pressed.
This also means that by knowing the length of the pool, the total elapsed distance can be easily calculated by multiplying the number of laps by the length of the pool.
Total Distance (meters) = Pool length (metres) x Number of Laps (N)
Open Water Swimming
Other Garmin watches not only have a ‘Pool Swim’ swimming feature, but also an “Open Water Swim’ swimming option.
The watches which track open water swimming use a combination of data collected from an internal accelerometer and GPS tracking. This helps combat the common issue of GPS drop-outs caused from the watch being submerged, an issue evident on the Garmin Forerunner 235.
When swimming in open water, it is still best to use the ‘Other’ sport mode, but ensure that the GPS is turned on, unlike with pool swimming.
When using the Forerunner 235 for open water swimming – or any other waterproofed GPS enabled watch for that matter – the main issue seen is inaccurate distances recorded. As can be seen from this open-water track from swimming with the Forerunner 235, the route tracked is very zig-zagged in nature, creating an inaccurate distance track.
This poor GPS accuracy when swimming is not due to the type of GPS hardware system (this is the same in all running and triathlon watches), but it is in fact a software based issue.
Garmin encode special algorithms into the software of their triathlon and swim watches for open water swimming. These algorithms analyse, detect and correct the constant changes in GPS signal strength whilst the wrist is underwater.
Unfortunately these algorithms are not written into the Garmin Forerunner 235 as it is specially designed as a mid-level running watch rather than a high-level triathlon watch. This is understandable from Garmin’s viewpoint as it creates a separation in their product lines, helping to segment the fitness market.
Therefore, with poor open water swimming accuracy the Forerunner 235 does not make for the best swimming companion. However, if this is your watch of choice, you can still make the accuracy for open water swimming better.
To try and make the GPS accuracy better, you want to try and raise the watch so that it is constantly out of the water rather than constantly dipping in and out. One way to do this would be to put the Forerunner 235 in the back of your swimming cap (near the top of your neck) so that it is continuously near the surface whilst swimming.
This comes with some problems such as not being able to see any activity data in real time, however from personal use, this isn’t too key whilst swimming and also isn’t the easiest to view in mirkier water anyway. Another consideration may also be the watch falling out the back of the cap so make sure it is tightly fitted!
Personally, however, I would recommend a safer and overall better option of a swim buoy. Many people swim with these in open water anyway and it is very easy to attach the watch to the buoy. This will again ensure the watch is above water and will give better results. These are not too expensive to buy either through Amazon.
Garmin Connect IQ Apps
Garmin Connect IQ is an app store full of apps that can be downloaded onto your eligible Garmin watch.
Without any swimming capabilities on the Garmin Forerunner 235, developers have spotted this gap and made a range of swimming based apps which can work on the Garmin Forerunner 235.
One of the most popular swimming apps for the non-swimming Garmin watches is ‘Pool Swim’ by developer danielp27. This app is perfect for pool swimming.
This app can be downloaded here.
For open water swimming, developer Robs_1976 has a popular app called ‘Swimming App Professional.’ But note this app is still in beta.
This app can be downloaded here.
There are many other swimming Connect IQ apps which are available from the Connect IQ store here.
Analysing Swim Data
With pool swimming or open water swimming recorded on the Forerunner 235 through the ‘Other’ sport mode, you can edit the sport mode in Garmin Connect after the activity to ‘Swimming.’
In the upper-right side of the activity page, you also have an edit activity option. This is where you can input the swim data taken from the activity. By referring to the earlier calculation of Distance = Number of Lengths x Length of Pool, you can input the total distance for the swim.
Garmin will then automatically calculate your average pace in min/100m, the standard swimming metric.
For swimming in open water where the distance tracked is mostly inaccurate but not always too far adrift; you have the edit option for this too. Just click on edit activity when in Garmin Connect and the distance can be correctly altered to the known distance.
Knowing the correct distance swam is not always easy as veering off course whilst swimming is an often result. However, if competing in a triathlon (Olympic swim distance is 1500m) you would know your distance exactly. Another option would be to track the route you roughly swam via MapMyRun.com and then add this distance in manually afterwards.
Heart Rate Data
Lastly, the Garmin Forerunner 235 introduced a wrist based heart rate monitor meaning the need to wear a chest strap is no longer a necessity for heart rate data.
In some fitness watches with both an in-built swim mode and an optical heart rate sensor, the heart rate data is switched off whilst swimming. This is due to poor accuracy as water can often interfere with the sensor and so lead to false readings.
For the Forerunner 235, no such switching off of the heart rate sensor occurs. This means that you are able to record heart rate data for swimming.
Having tested out this feature, I can say that the results are not too bad but not something to go off with absolute certainty. The heart rate readings seemed to steadily increase over time, in line with the increase in effort from swimming.
However, the data was most likely an underestimate of the actual heart rate data as seen from this particular 35 minute swim where the average heart rate was 104 BPM.
With this accuracy in mind, Garmin have released a set of new heart rate monitors. There are two new heart rate monitors available, one is called the ‘HRM-Swim‘ and is designed specifically for swimming.
The other heart rate monitor is a more advanced ‘HRM-Tri‘ designed to be compatible in and out of the water.
Both off these heart rate monitors are compatible with any Garmin ANT+ watch, including the Forerunner 235.
Both of these heart rate monitors can be purchased on Amazon or in a bundle together. If you are someone who is keen on heart rate training then I would certainly recommend these to ensure a higher level of accuracy when swimming.
Despite the Garmin Forerunner 235 not being designed for swimming, I have been able to show that it meets most requirements of an recreational or amateur swimming.
The results are probably best and most accurate in pool swimming as the distance which you are swimming is know, however heart rate accuracy is not going to be exact.
Open water swimming is also clearly possible but you will be foregoing the tracking accuracy as well as the heart rate accuracy. However, there are good alternatives for the GPS tracking with the use of a buoy.
But given the waterproofing of the Forerunner 235, it is a more than good enough option for the casual swimming who occasionally swims alongside their running and cycling, making the Garmin Forerunner 235 an ideal all-round watch!
Feel free to ask any questions – thanks for reading!
You can buy the Garmin Forerunner 235 below to help support this site.