The Charge 3 is the most advanced fitness tracker in the market, according to Fitbit. It succeeds the critically acclaimed Charge 2 that was launched in 2016 and comes with plenty of improvements.

Its touchscreen display is around 40 per cent larger, but it weighs 7g less by using aerospace-grade aluminium for its case and buckle (the Charge 2 has a stainless steel case).

It also loses the sole physical button of its predecessor, with an inductive button on its left instead.

This allows for better waterproofing. The Charge 3 is water-resistant to a depth of 50m. You can swim with it, unlike the Charge 2 which is only splash-and rain-resistant.

The Charge 3 comes in many case colour and band combinations. I reviewed the special edition graphite case version (with Fitbit Pay support) with the white sport band. The sport band has holes, making it breathable and very comfortable to wear.

The Charge 3 monitors daily physical activities, logging fitness information such as steps taken, calories burnt, stairs climbed and heart rate.

It automatically recognises different exercises such as runs, walks and swims, and tracks them accordingly.

The automatic tracking works as advertised, as long as you do an activity for at least 10 minutes.

My walks and runs were accurately tracked when the Charge 3 was connected to my iPhone. But because it does not have built-in GPS, it uses the paired smartphone's GPS to track distance. When I ran without the paired smartphone, I found it added almost 1km to my usual 5km jogging route.

Getting it to automatically track a swim is more difficult, as you need to swim constantly for 10 minutes. It was a problem for me because I am not a strong swimmer and usually need to take breaks between laps.

The easier option is to use the Charge 3's Swim mode, where you set the pool length before starting the swim. After you finish your swim, you can find the lap, distance and pace information in the Fitbit app. It tracked all my swim laps accurately.

The Charge 3 was very accurate in step tracking. My results differed by no more than 2 per cent from my calibrated Apple Watch Series 4. For heart-rate monitoring, its measurements differed by only three or four beats a minute from my Apple Watch.

Sleep tracking continues to be excellent. It automatically tracks the amount of time you spend in light, deep and REM (rapid eye movement) sleep cycles, as well as the time you are awake.

While I have no way of knowing how accurately it tracked my sleep cycles, I can say that it was very accurate in pinpointing the time I woke up to use the bathroom.

Battery life has improved to a week, from its predecessor's five days. But it continues to use a proprietary charging cable, which might be an issue if you forget to bring it along when you are travelling.

In addition, the Fitbit Pay contactless payment currently supports only OCBC and UOB banks. I did not test this feature as I do not have credit cards with either bank.

•Verdict: Apart from lacking a built-in GPS, the Fitbit Charge 3 is the almost-perfect fitness tracker.