My Detailed Initial In-Water Impressions of Garmin Mk3i

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CONTINUED FROM THE PREVIOUS POST...

Dive Features and Performance
Well, believe it or not, there’s not a ton to say here. While underwater, the Mk3i performs almost identically to the Mk2i, which is good. The biggest change, of course, is the screen. The Mk3i’s screen is like a beacon in the dark compared to the Mk2i. It made me wonder if the Mk2i’s screen was just really bad or if the Mk3i’s screen is just really great (I think it’s a little bit of both). I did dive with both of them on separate wrists, and the comparable difference in screen brightness and clarity was night and day (no pun intended). The only other noticeable difference to me was the strength of the vibration on the Mk3i anytime an alert occurred. I feel the vibration is much stronger on the Mk3i, but maybe I was extra sensitive today.

Overall, the dive performance was excellent, and I felt like I was just using a refreshed version of the Mk2i instead of a completely new computer. And I say that in a good way. The Mk2i is solid and stable and it appears that Garmin has mostly taken a “leave good enough alone” approach with the Mk3i.

One new feature that Garmin has touted is the new DiveView Maps. These maps provide information about depth, terrain, and the location of popular dive sites. I did play with this a bit, but I’m struggling to understand its practical use. The data is too limited, and the screen is too small for real dive planning. I also found the interface to be complex. Perhaps, if you’re unfamiliar with an area, you can pull up the map to help discover new dive sites. However, this would assume that you’re on your own boat and have the luxury to explore sites on a whim. It also appears that the dive sites utilize a database that Garmin has used for a long time, which automatically displays dive site locations in your Garmin Dive app. This is a very neat feature when it works. However, I have found that many popular sites here in South Florida are either not in the database or are not picked up after you’ve completed a dive.

Diving with Both Computers at Once (Mk3i and Mk2i) + Multi Transmitter Support
So, I wasn’t just diving with both the Mk3i and Mk2i to experience the differences side-by-side. I always dive with redundant computers, and this will be my new setup moving forward. A few observations should be noted about this type of setup: First, the T1 and T2 transmitters are forward and backward-compatible with all Garmin computers supporting AI. The main difference is that the new messaging feature that Garmin has touted requires T2 transmitters (which is why I didn’t test this feature). Garmin publishes a good compatibility chart here but the reality is that everything just works well with each other. After pairing my transmitter with the new Mk3i, my primary tank pressure could easily be viewed on both computers simultaneously (and they were always exactly the same PSI number).

Furthermore, both the Mk3i and Mk2i can connect to multiple secondary transmitters (max of 5 cylinders with the T1, 8 with the T2). This could be your buddy’s tank or your second post if you’re diving doubles and are a gadgethead who wants this. Your buddy can then set up his cylinder as his primary, and you can set up his transmitter as a secondary. The computers have separate screens allowing you to see your connected transmitters. However, you can also display two transmitters on the main screen, which is very nice. I tried this myself today when a dive buddy allowed me to pair his transmitter and vice versa. We only dived together for about 5 minutes to try it out, but it was quick to set up and worked flawlessly until we were about 15 feet apart (maybe more; I’m bad at judging these things).

If you are wearing two Garmin computers, they will both upload to the cloud by default. This means that you will have duplicate dives in your Garmin Dive and Garmin Connect Dive logs. You should know that each watch has a separate dive counter, which you can reset to whatever you want. For example, my first dive with the Mk3i was uploaded as dive #1, while the Mk2i uploaded that same dive as dive #91. I then changed the Mk3i dive to 91, and both computers subsequently numbed the next dive as Dive #92. You can decide if you want to delete one of the dives, and there’s probably a way to stop one of the computers from uploading altogether if it really bothers you (I have not researched this).

Another interesting thing to note is that all the statistics about my dives were identical between the two watches, including things like N2 loading, OTUs, etc. This is unsurprising since they probably run the same code for these core algorithms. One quirk to note is that the Mk2i consistently showed longer dive times by up to 20 seconds. Is this a setting thing? Are they using different types of depth sensors? I'm not sure, but it's not a big deal.

Battery Life
The battery on these Garmin computers is nothing short of amazing. Back in December, I kept forgetting to charge my Mk2i in the Maldives, but the computer still had more than 40% battery life after three days and six dives. Luckily, it appears that Mk3i hasn’t lost anything regarding battery life. A few quick stats:

8:00am: I turned the Mk3i on, and the battery was at 97%. Started wearing it for the day.​

2:26pm: First dive begins, run time of 41:25​

3:53pm: Second dive begins, run time of 38:11​

5:25pm: Captured photo of computer battery below. Battery is at 93%​

After two dives and nine hours on the wrist, it ate up 4% of its battery. That’s pretty good.

There are a couple of important things to note. First, I do NOT wear these computers outside of dive days. They are not everyday smartwatches for me, so your mileage may vary depending on your usage characteristics. Second, I don't have the screen set to "always on", which means that it wakes up when you turn your wrist - this does save on battery life. Finally, I *do* have it set to the brightest screen setting, which drains more battery than its slightly dimmer default setting.

View attachment 824392
[Mk3i after 9 hours on the wrist and 2 completed dives.]

Summary
So, I’m not going to discuss competitors - we all know what’s out on the market, and we know that Garmin and Sheerwater are most certainly going head-to-head when it comes to diving computers in the wristwatch form factor. I also know from my journey and that of friends that people will jump ship from one brand or form factor to the other. These are all great computers, and you’ll just have to research what is best for you. I won’t examine issues concerning wristwatch form factor, price, or specific brand attributes.

That said, the Mk3i is an excellent computer with good improvements over the Mk2i. Of course, the screen is the real difference here. The better battery life is great, especially given the new screen technology - it’s best-in-class.

So, if you were on the fence, should you buy it?

This should certainly be a contender if you’re looking for a new dive computer. It’s a top-tier dive computer, and I think it’s suitable for most divers (I can’t speak to how this would be valuable to CCR divers, so I’ll ignore that and assume you will be running a Sheerwater controller, anyway). You can save $200 today if you buy the older Mk2i while supplies last, but I think you’ll be disappointed in yourself if you go that route.

If you have a Mk2i (or another computer brand) and want a secondary, redundant dive computer, you should consider the Mk3i. I’m very happy with my own approach here.

If you have a Mk2i and are tempted to upgrade to the Mk3i, replacing your Mk2i, I don’t think the decision is obvious. At the end of the day, the Mk2i is still a great dive computer, and it will continue to serve you well for years. Yes, you’ll like the Mk3i better, but you might like $1600 in your pocket even more. There’s no denying that Garmin computers are at the top of the market regarding price point.

Safe Diving!

great review and super helpful, thanks!