The Bluetooth G-Shock "Casioak" GA-B2100 In Depth Review and App Tutorial

Casio's GA-2100 watches have been wildly popular since their introduction about four years ago. In the meantime, many variations have been released with different colors and materials. The latest versions to catch my attention include "Tough Solar" battery charging and Bluetooth technology to keep the watch set to the correct time, right down to the second. Many watch enthusiasts refer to these 2100 series watches as "Casioak" watches because they share a similar case shape with the Audemars Piguet Royal Oak watches. Personally, the Royal Oak watches weren't on my radar and, perhaps, the main reason for that is they are literally unbelievably expensive. (I challenge you to do a quick online search for the prices of genuine Royal Oak watches and then you can tell me whether you also find the prices to be literally unbelievable.)
One of the fun things about these Casioak watches is that they're amazingly affordable and, if you want to be adventurous, you can find lots of kits to modify them too. Perhaps you can make a "Casioak" look amazingly similar to a Royal Oak. But I prefer to have lots of fun with this GA-B2100 while keeping it looking exactly the way it was made by Casio.
The model in this video is a GA-B2100C-9A which uses module 5689. In addition to the Tough Solar technology it has G-Shock's legendary shock resistance and 20-Bar water resistance. It has a World Time mode, 24-hour stopwatch, 1-hour countdown timer, 5 daily alarms and an hourly signal. It can connect to a smart phone or tablet using Bluetooth and the "Casio Watches" app. Those who prefer not to use the app will still enjoy almost all of the watch's functions. The "Reminder" function is only available through the app and the automatic time synchronization is only available through the app. Otherwise, the watch is able to keep time with its quartz accuracy of plus-or-minus 15 seconds per month.

[@12ent12]

Man, can’t get enough of your g-shock reviews

[@f1hotrod527]

My first Casio was the green version of this watch. I like it very much. It fits very well on wrist, and is a handsome timepiece. It has been followed by a couple squares......... god help me.

[@tydshiin5783]

Honestly, I find the squares sitting in my wrists better than my ga2100, but god help us

[@gamoya12]

U r the best casio reviewer in the world. I follow u from morocco. I love casio. Niw i have 9 watches

[@motorhead20]

im even more excited for it to arrive now, changing the order of date is so nice

[@elim9780]

This watch is just fun.. Have the same yellow one. I just swapped out the bezel and straps with a black GA2100 and the parts fit. That should help out some of the modders out there. Great work @greg! Loved your Pro Trek reviews. Helped me a ton when I first got my PRG 600

[@theloneranger2101]

I have just recently purchased myself this watch, it's the all black version, or as I like to call it the Stealth Version, and I think it's a very clever watch when connected to the App on my Smartphone. This review of this Watch is the absolute best I've watched on KZbin, and there are many indeed, some are okish and some are absolutely terrible. But this review stands out as the absolute best, with a very nice closeup of the watch face all through the video, plus going through all the functions clear and concisely, and demonstrating the App functions, all wonderfully done.👍 So to other KZbin reviewers out there, this is how to do it, no silly unboxing, showing all the sides of the box it came in and the paperwork included in the box, all taking about 10 minutes before you show the actual item in the last 2 minutes of the video review.😠. Well done Greg, an excellent review. 👍 You'll be pleased to know I have now subscribed after watching this video from your channel for the very first time, it impressed me that much.👍

[@billrosich7317]

I absolutely love this watch! I have the "standard" black version with the positive display. The Bluetooth connection/app is my favorite part. I've owned countless G-Shocks over the years and I must admit to always being intimidated by all of the features. I've never familiarized myself with how to set all the alarms, stopwatches, countdown timers, etc. Which button to push? How many times to jog it to the desired setting? Which button to toggle the power saver on/off? With this watch, you can easily control all of the functions with a swipe of the finger on a smart phone. Brilliant!

[@EffendiChung]

Absolutely love mine, I also purchased the yellow one a year ago. A bit of a problem though, the yellow stained a lot. Is there anything I could do to remove the staining? This is my only bright coloured watch I have, and I grew quite fond of it.

[@bradcarpo5917]

I allways value your professional advice, so I'm getting one like yours with my Christmas bonus this year. This watch looks great and very useful for me. Thank you, I watch your videos often.

[@GoodTimekeeper]

I hope you like it. Merry Christmas.

[@bradcarpo5917]

Thanks, can't wait.😊

[@rctezluh42069]

I have this same watch and it is really fun to wear! upvoted!!!

[@loganholmberg2295]

I was really happy converting my 5600 to a metal case. Since these have never fit my wrist this looks like they finally have the features I want to get this and convert it to an aliexpress case.

[@RobWhittlestone]

Hey Greg what a great video! I have the GA-B2100 as a favourite vacation watch, because of the automatic synchronisation, indestructability and lower probaaility it will be stolen. I'm amazed how easily you play with the buttons. I find them illogical and confusing. I always use the app!

[@TheMegaPhilko]

Dear Mr. Anderson, I find it really funny, that we both have almost the same taste AND get/buy the same watches at almost the same time! I got this "CasiOak" in yellow as an easter-present for myself, too & a similar thing happened with the gwm5610 with the blue display (I don't recall the exact model-number just right now), where you uploaded a review of it just a few days after I bought it myself... So I HAVE to like your content, since it really fits my taste! But your videos and reviews are always good & informative so I follow your channel for a long time now - please keep on with your good work!!! Best wishes and greetings from a fan (of your "art" and presentation-style) 'n subscriber from Hamburg, Germany Philip :-)

[@GoodTimekeeper]

I don't know if I should tell you which watch I plan to buy next week or just surprise you. Or maybe you already have the next watch I'm planning to buy! I'm thinking about a G-Shock which costs around $150 and I'll order it from Japan. It was introduced in the year 2010 and I don't know how much longer it will be available so I'm thinking about buying it now while I still can.

[@TheMegaPhilko]

​​​​​@@GoodTimekeeper now that you've given me a few possibilities of outcomes (maybe I own it though 😂), I just NEED to know what kind of watch that is... Maybe the gw3500? That I would really recommend and it is from 2010!!! I would guess, if there weren't too much options to chose from... So please don't stretch the torture (is this an expression in english alright? I just translated a very basic german expression) and tell me/us more about it!! I promise that I won't buy it just fo the sake of having the same watch... though I might be tempted!!! :-) Greetings from Hamburg again Phil :-) PS: I ordered a GWF1000 a few days back - but thats just by the by 😊 PS2: What REALLY interests me though (maybe you too?) is the following question: How to order the new DW5040 - the 40th anni. model! Do you have any ideas for that? I know it is not multiband and/or solar, so it might not fit your bill... But I am really tempted with that model! Any advise would be really aporeciated, sir!!! :-)

[@GoodTimekeeper]

When I think about a 40th Anniversary release I guess it’s going to be very expensive so I might hold out for Multiband 6 and Tough Solar. But I am waiting to see if there are any other 40th Anniversary watches which haven’t been announced yet. Meanwhile, I was going to buy the GWX-5600 which was first released in 2010 but I am also thinking about the GWX-5700 which uses the same module with a different case.

[@rickrounds2173]

Hi Greg, love mine too. The app is easy to use too. Just enable Bluetooth on your phone and you'll never have to touch the watch.

[@ralphus555]

Great review. I have this iteration and it's great. Only complaint I have is that the lume on the hands is poorly applied. The lume on the minute hand is rather splotchy.

[@tydshiin5783]

Never thought I'd be early to watch a Greg Anderson video Oh btw the mode/battery hand does not have lume on it unfortunately, it would have been nicer if it did but it's just plain white paint instead of red or black to contrast the yellow

[@pauljosephbuggle3722]

I have one. I like that it is really light so I wouldn't mod it to metal. The only thing I don't like is that you can't see the day and date at the same time. I would have liked an automatic light but then you can't have everything is such a slim analogue watch. I put a black strap on mine and it looks really well. I've got a lot of compliments since I did that as it looks more classy. The black strap goes really well with the black face. All in all I am very pleased with this watch. I love the Bluetooth app because it makes everything so simple. I wouldn't have bought it if it has no solar charging or Bluetooth. Again, I wouldn't have bought it if it had a negative display.

[@GoodTimekeeper]

I guess there's only so much they can show on such a small LCD window on the face of this watch.

[@mediaplayer2150]

Ti seguo da un Po mi piace molto il tuo canale e i tuoi contenuti,i canali nella mia lingua parlano sempre dei soliti 4-5 maison, Rolex, longines, Hamilton e svizzeri...che noia sempre le stesse referenze! Bellissimo questo un'ottima evoluzione del 2100. Preferivo il segnale radio al Bluetooth però. Lo prenderei, magari non giallo pero! Saluti.

[@spacemanschannel6380]

I think the Bluetooth and the app synchronisation is a good feature, in countries where atomic clock is not available. The settings are also easier to handle on the large smartphone than on the tiny watch display. However, I decided for a watch with Multiband 6, because I specifically wanted a watch that works without internet and smartphone. With solar charging, and Multiband 6, you have a small independent device that works like forever.

[@jameschristiansson3137]

The Casio Oceanus T200 has both Bluetooth and Multiband 6. Wish all Casio watches were this way.

[@MarkM58]

Bluetooth seems to be replacing the Multiband 6 because it is good anywhere there is a cell signal.

[@tydshiin5783]

Yeap, living outside the ranges of the towers is actually hard to justify getting any atomic watches

[@jameschristiansson3137]

Some Casio watches do both.

[@mrsmith8436]

I think bluetooth for this function is pointless and defeats the whole idea of a solar watch that can sync its own time. The atomic sync or even GPS at least keeps the watch independent and it does not transmit anything or connect to anything it only has to wake up and receive a signal once in a while. Smartphones are making people ignorant and lazy. So to use the bluetooth feature I have to first have a smartphone and also download an app and then connect the bluetooth to the watch. Then I have to run the app. On top of this what if you don’t have cell service? Moreover why not simply look at the clock on your smart phone which you must have anyway to use the bluetooth sync app🤔. I prefer my watches to not be connected to anything or transmit anything. I can just reset the time manually.

[@d3xmeister]

I love Bluetooth for travel (Bt is pushing the correct time once the phone changes time zones) but in the long run Multiband is more reliable. Especially in Europe radio signal will never be turned off (not in the next 50 years) but with Bluetooth, in some years the watch won’t pair with modern phones/apps any ore. There are already Casio models from 2013-2014 which won’t pair with phones anymore with BT.

[@MarkM58]

@@mrsmith8436 To each his own. These watches work just fine not connected to anything. Those of us that enjoy 21st century technology will enjoy the additional capabilities.

[@kennyrmrz]

Thank you for this review! Is it possible for the display to show the DATE on the top and the DAY on the bottom or vice versa? Or can you only display one of those two?

[@freeperrin]

Elite review

[@freeperrin]

Thank you 🙏🏾

[@khalidsuxx]

tq for this im blur with all this bluetooth app features and u help me

[@vesselinkrastev]

It might seem petty, but I really don't like that you can't have both the date and the day of the week displayed at the same time. All of the watches I currently keep in rotation can do this and I'm really used to it. I don't want to wave to press a button every time I want to see the other info and then press the button again a couple of times to cycle back to the original position. The more basic movement can show both, but then it doesn't have bluetooth and solar.

[@glenncaukill1320]

Hi Greg I have this watch in the black and the yellow, during the winter because of lack of use both my watches stopped due to lack of use , my yellow one changed no problem, my other one won't seem to charge , any ideas?

[@ALC-bd1pm]

Hi Greg, I also got my hands on the GA-B2100-1ADR (black color version) in January! Same deal as with your yellow one; the positive displays, it's solar-powered, and has the Bluetooth feature. I also thought about customizing it with a metal mod, but then realized that was too extra (both in weights and price) and decided to just let it be. So far. I'm happy with this timepiece and loving it so far! Perhaps the next watch that I am looking for is the G-SQUAD DW-H5600, just introduced yesterday. It combines the iconic G-Shock square shape with MIP LCD display, heart rate monitor and fitness tracking functionality.

[@mediaplayer2150]

Casio non deve però cadere nella tentazione di creare smartwatch... Spero mantenga la linea attuale

[@dgross2009]

To me the black version was not as readable although it also has the necessary positive display. I took a black strap off another casio and slapped it on the yellow to tone it down and it becomes much more wearable. One of my favorite watches. You need to connect to bluetooth before every use however or the time gets way off the mark.

[@e28forever30]

You know it connects and corrects automatically ?

[@dgross2009]

@e28forever30 It's not automatic unless I'm missing some kind of setting in the app. My routine is to open the app and then activate Bluetooth on the phone. If it connects successfully then it will automatically correct the time. My point is that without this feature it is by far my least accurate casio watch

[@e28forever30]

@@dgross2009 Why make it difficult. I can’t understand why people insist on turning their Bluetooth off. Just leave it on, and keep the app open in the background. Pronto, the watch updates itself without any hassle..

[@MintyMintys]

Greg can you do a review on the casio aeq110w-1AV

[@tonychen3368]

This guy is the one that's at $160, I have seen the GAB2100 1A in person in a local Jewelry store and it's still not sold yet.

[@edk2221]

They say Casio is God Tier, well so is Greg Anderson!

[@shivamnrutya]

time stamp 3:22 ( does that green Gshok have multiband? ) because I can not read multiband 6 in green watch

[@Anurag.01]

I have the green color of this watch, and i don't understand why it's not connecting to the app. Can u help ?

[@Uli4Munich]

Thanks for your in depth review. Have one in yellow since one week. A very nice toy, all this little useful small features, the color is a statement, indeed GREAT FUN! Oh, this is comment 100 😀

[@Thunder_IITian]

can we control music from watch as it ihas bluetooth

[@dnystrom22]

I really hope they do come out with a multi band 6 version and drop the Bluetooth, I work in an office where Bluetooth devices are not allowed. Hope for this because if it didn’t have Bluetooth the all metal solar version would be my favorite edc watch.

[@traviswalker8933]

That's not happening anymore as BT is the new favourite on budget G-Shocks.

[@GoodTimekeeper]

I wouldn't be surprised if there's a Multiband 6 version eventually, but I decided I didn't want to wait for that just in case it never happens. I really enjoy my Gravity Master watch even though that particular model is Bluetooth-only.

[@delmund]

But you dont work at the office 24/7 right? Quartz movement is very accurate, and after office hours you can sync.

[@smartcar8]

Hi, I have a question. When I sync my GA-B2100, it is off by 15 seconds compared to my G-Shock 5610. The difference is roughly 15 seconds. I believe the 5610 shows the correct time as it syncs with the atomic clock and syncs with the time on my cellphone. Any ideas on how to correctly sync the GA-B2100?? Thanks!

[@HarryCallahan-tf3qr]

He's ignorant he's not replying to anyone 🤦🏻‍♂️

[@HarryCallahan-tf3qr]

Are all the yellow versions the same yellow because some look more yellow than others?

[@Daniel-kn3dk]

Excellent watch. How much time needs a solar watch to charge battery from empty to completly full?

[@mediaplayer2150]

Poche ore

[@GoodTimekeeper]

There is some information about this in the owner's manual for Module 5689. If the watch is in full sunlight it will take 3 hours to go from a dead battery to a medium charge, then 24 more hours to go to a high charge, then another 7 hours to go to a full charge. It will take longer if the watch is indoors and/or under a light source which isn't direct sunlight.

[@ElPashmino]

I bought this one with the intention to use the reminders constantly but they just suck. It will only show the last reminder you set up on the app and forget about the other previous reminders even if they are closer on date to current time. There's no way for cycling through the "active" reminders and the notification will blink even if the date in the reminder is set yearly

[@dayumboydayum8461]

Hi, I’m hoping you can really help me here. Do you know if there is a way to disable the Bluetooth from the watch? Sometimes you can’t wear these devices in aircraft or hospitals so I really need to find out. Thank you so much

[@GoodTimekeeper]

If you don’t pair the watch with a phone and you don’t hold down the button on the watch to attempt a phone connection then it will effectively be in “airplane mode” and will not put out any radio activity. If it IS paired with a phone you can still turn off the Bluetooth “auto time adjustment” by pressing a sequence of buttons as described on page 17 of the manual, which you can download from Casio’s website. Module 5689.

[@elim9780]

On IOS if you want to use bluetooth from time to time.. In the App with connected watch To my watch >>> Time Synchronization >>> Automatic Time synchronization settings >>> Automatic Time synchronization (Toggle off) after that Automatic synch will be off. Kill your app and you will see the watch disconnect. Now it will only connect when you physically press the button to put the watch in pairing mode and then start the app. Then it will synch the time and the rest of the "stuff". On the synchronization app page it states- "This obtains the time accurately using a system exclusive to Casio. In some cases, the time on the watch and app may differ from the time on vour smartphone. Please turn the feature off when on board an airplane or in other situations in which Bluetooth connection is not desired. For watches which have time svnchronization features using GPS or radio waves, turning this function off will also terminate these other time synchronization features."

[@AlexBaldwinFTW]

Sorry if i missed this but can the top difital screen only ever show seconds?

[@GoodTimekeeper]

In the Home timekeeping mode and World Time mode it only shows seconds up there.

[@btc76]

it's amazing though how cheap the case/strap feels.. feels rough on the skin when you're used to a silicon strap.. that's the next thing I will do, change the strap.

[@nuhuh9893]

It's disappointing that with so many features including an app that Casio didn't include something as simple as auto-repeat on the countdown timer. 😠

[@skipinkoreaable]

I can't help wondering what you wear with your yellow watch.

[@damyr]

It goes well with a red business suit and yellow shirt.

[@FiremanFrach]

Not a big fan of the shape, but nice watch.

[@aladinsarsipeus]

im returning mine im not thrilled about the build quality for $140

[@mikebikekite1]

I have the all black version of this watch. If you're looking for a "good time keeper" or a stopwatch etc then the all black version isn't for you. I find it difficult enough seeing the hands on the all black model let alone the info on the LCD. If you want a cool watch then the all black one is hard to beat.

[@d3xmeister]

Wait, modern Casio Gshock, with Analog dial, multi-dial, and dual zone digital display, that won’t show the day of the week ? What the hey ?

[@sandsgrainofsand5320]

there is an option to display the day of the week..

[@d3xmeister]

@@sandsgrainofsand5320 But you lose the date.

[@renobodyrenobody]

Ha thanks, for me giving a mail in order to have a sync with the watch is a no go. The previous apps where ok. A new wath = a new app from Casio? F*** zem.

[@wb4514]

If you don't care about using the app or bluetooth just get the GA2100.

[@GoodTimekeeper]

But I also like the Tough Solar feature on the Bluetooth version.

[@danschlacks7188]

I'll get one when it has atomic time.

[@GoodTimekeeper]

I will also get one when they add an atomic time receiver (Multiband 6) but nobody has made any promises that they will. So I thought it would be good to play with this one sooner rather than later.

[@danschlacks7188]

@Greg Anderson - The Good Timekeeper Thanks for your response. Hopefully they will some day!

[@Chrishagen]

Unfortunately these solar casioaks will not hold their charge in countries that do not have year round sunshine. My 5610 and wave ceptor watches are both solar casios and remain at H charge even under artificial light indoors in the Northern European autumn and winter. I had to buy a LED lamp to prevent the G2100 solar completely discharging. First Casio watch I have had issues with. If you live in a cooler country, would advise getting the previous generation of battery powered casioaks, whose batteries usually last 3 to 5 years anyway.

[@JK18.]

I'm not sure I understand fully if the watch charges through any light then it shouldn't matter what country or the weather?

[@Chrishagen]

@@JK18. right, India and Belgium have equal amounts of sunlight on average.

[@JK18.]

@@Chrishagen got ya I just put my watch in the window in the morning for a couple hours and my battery stays on hi

[@mrsmith8436]

I think bluetooth for this function is pointless and defeats the whole idea of a solar watch that can sync its own time. The atomic sync or even GPS at least keeps the watch independent and it does not transmit anything or connect to anything it only has to wake up and receive a signal once in a while. Smartphones are making people ignorant and lazy. So to use the bluetooth feature I have to first have a smartphone and also download an app and then connect the bluetooth to the watch. Then I have to run the app. On top of this what if you don’t have cell service? Moreover why not simply look at the clock on your smart phone which you must have anyway to use the bluetooth sync app🤔. I prefer my watches to not be connected to anything or transmit anything. I can just reset the time manually when it can’t sync atomic or GPS. Not to mention how much more drain bluetooth will have on both the watch battery and your smartphone😉

[@mediaplayer2150]

Yep

[@GoodTimekeeper]

The Bluetooth connection shouldn't have a significant impact on the battery because it can transfer data in just a matter of seconds. I suppose there are many reasons why this watch doesn't check all the boxes for everyone. But the entire line of "CasiOak" watches has apparently been a huge success for the company anyway. Even though there are over 100 variations of the "CasiOak" it still came down to just two which caught my attention and just one that I actually bought. I have decided to have fun with it even if it can't do everything I'd want a watch to do. For what it is, I think it's packed with a whole lot of great features.

[@TheChico868]

I'll tell u secret. I only use my Gshock to tell time.

[@Rafal.L]

Too yellow for me

[@Bottomburbsburnbums]

Don’t buy if you have 8+ inch wrists - it won’t fit. 😩

[@d3xmeister]

The Casio Oak is a cash grab. Why are the bands and bezels double or triple the cost of the Squares, when they are made from the exact same materials and mostly the same size ? The watches are also more expensive even though they pack much less tech in them. And the build is questionable. Where is the soft metal cage for the movement ? Where is the soft rubber cage for the movement ? Even the simple square digital G-Shocks have those.

[@GoodTimekeeper]

Somehow, Casio really struck a nerve among watch collectors with the "CasiOak" and I suppose they're entitled to make a healthy profit because of that. But I didn't understand the massive popularity either and I obviously waited a few years before I thought this "CasiOak" was interesting enough to make me purchase one. I suppose they're limited in how much technology they can pack into this while still retaining the form factor which has made the watch so popular. It will be interesting to see how long the popularity will last and to see what else Casio will do with this design in the future.

[@d3xmeister]

@@GoodTimekeeper You are absolutely right. Thank you for replying.

[@e28forever30]

I owned this yellow version for a short while and didn’t connect with it. It works fine, but the display is too small and the band was squeaky as hell where it connects to the case.

[@ElderPinto254]

i bought it but its to big wen i wear it it makes me cry just dont like it ...

[@franciscodeleon8680]

Hahaha kawawa ka naman isa na nga sa maliit na model ng gshock yang casiooak

[@damyr]

There are smaller versions, 37mm in diameter. Check it out.

[@ElderPinto254]

@@damyr yepp you are wright i got the first run

[@donaleeesio]

I don't understand, what is this mentality "I don't want to spend large money on a watch"? Is it to say that wrist watches are insignificant objects? I'm not saying that I commend those who spend hundreds of thousands if not millions on timepieces for silly amusements or to make their points or perhaps to join a club! Infact they are equally as idiotic in my view. I believe there has to be a balance. There is a certain amount of monetary limits where a timepiece can be superbly made and offered with great costumer service, everything within that limit would be reasonable, those who choose to go above or below it it's their own problem and this problem comes from obsessions and mental challenges that are highly contagious.