Whit these kind of adapters:

You could use nato or zulu strap ( nylon or leather) from 22 to 24 mm or another nylon strap .
Whit these:

Nato, zulu ( 22 mm most of the times) and metal bracelets.
I asume that the Ga 2100 got the standar 16 mm lug so those fit perfect.
Where buy it?
E bay
Amazon
Hope this help you.

 

JaysAndKays makes metal adapters for the GA-2100, but I don't know if they have any that fit the GMA-S2100.

JaysAndKays® Metal Adapters Kit for GA2100 GShock Casio Oak GBM2100 GAB2100 2100 | eBay

For your service. Adapters color: Black, Gray, Silver or Gold. Kit includes - (1) pair of stainless steel springbars (20mm or 22mm, per chosen strap width option).

www.ebay.com

 

Second JaysandKays, I use them for my G

 

SKX has some cool modifications.

https://www.skxmod.com/collections/casio-modding-kits

Edit: Disregard. Did not see yours was a slim version.

 

I have ordered standard sized GA2100 and GAB2100 CasiOak watches, as I think these watches will allow me greater selection of aftermarket straps vs. the Mini CasiOak watch.

Thank you.

 

Be warned with the 2100's and using different straps other than the OEM quick release straps - I believe that the lug holes are not a good fit for standard G-Shock spring bars, it's been mentioned on here before but I can't recall if the holes are too big or too small.

 

What's bad about the strap? I was thinking about getting 2100 but now hesitant

 

It's just not as comfortably flexible/conforming to the shape of my wrist as I am accustomed to with NON G-Shock straps.

The watch is fine - if you like it!

Strap could be better. And, with some perseverance... better options will be applied!

 

I found a good thread for GA2100 straps:

Straps for GA-2100

Hey all, just ordered my first G-Shock, a GA-2100-1AER. Tried on my friend's blackout the other day and loved the look, but I wasn't a fan of the stiff strap. Is there a softer Casio strap that can be swapped in? I read somewhere that the DW5600 band fits, but I can't find anymore info on it...

www.watchuseek.com

 

Jay and Kay's adapters are your friend, then you can fit any strap you want. They sell them on eBay

 

Jay and Kay's adapters are your friend, then you can fit any strap you want. They sell them on eBay View attachment 17019878

Very nice looking bracelet, BTW. I have your exact same watch model arriving tomorrow! Looking forward to it.

 

@Wardogz - very good, sir. Thank you.

 

Right back at ya, wearing mine today in the office, I reckon I check the time more often when I'm wearing this model

 

For fun,
After a few years, I was fed up with the genuine strap on my gwn-1000c-1aer
I bought another strap that fit the gwn-1000c... the "9aer' version.
Result, to me, is awesome

so many options with G-shock to get "old" watch to look like a new one !

If G-shock didn't exist, someone should invent it !
Fortunatly... G-shock exists !

 

The JaysAndKays adaptors open doors to fun options.

 

They are not supposed to be soft, they are made to last.

Yes, you can get adapters allowing for great comfort, but they make the watch look silly.