Casio · ref GA-2100-1A1 · 2019–present
Casio launched the GA-2100 in 2019, and fans quickly named it the CasiOak because its eight-sided bezel looks a lot like an Audemars Piguet Royal Oak. The shape actually traces back to the first G-Shock, the DW-5000C. Its Carbon Core Guard case is made of carbon-reinforced resin, which let Casio get it down to 11.8mm thick and 51 grams. That made it the thinnest G-Shock of its day and the lightest analog-digital one. The all-black GA-2100-1A1 sold out for months, and counterfeiters copied it as a result. The hands and the small screen both run off module 5611, which has world time in 48 cities, a stopwatch, a timer and alarms, and it keeps G-Shock's 200m water rating. The downsides are a tiny LCD and weak lume on the blackout version. Aftermarket metal bezels and straps are popular on it, so decide whether you want stock or modded before you shop.
A hard knock or a strong magnet can push the hands out of line with the digital time, and the manual covers how to reset them. The resin bezel scuffs and the strap cracks with time, and many used ones carry aftermarket parts.
Buying guide
A used black GA-2100 from a US seller asks $73–92 delivered, and the $87 one with its tin is our pick. There are about 118 listed, most at $120–180 delivered, because Japan resellers fill the search with $30–60 shipping, and we pool the colors and special versions like the SRS, which ask more. Compare the hands with the digital time in the photos, read GA-2100 and module 5611 on the caseback, check that the bezel and strap are Casio's own, and check the seller's feedback and return policy on the item page. The all-black GA-2100-1A1 is the most faked, so be wary of a cheap one from an unknown seller and compare the dial print with Casio's photos.
$71.35est. delivered
The lowest delivered GA-2100 here at $71, a gray one with its tin, from a US seller. It isn't titled tested, so ask for a photo showing the hands and the digital time agree.
Casio G-SHOCK GA-2100S Analog/Digital Quartz Gray Resin Octagon 200m w/tin
$86.82est. delivered
A black GA-2100 with its tin at $87 delivered from a US seller, well under the band. Read the caseback in the photos for module 5611 and check that the bezel is stock.
Casio G-SHOCK GA-2100 Black Analog-Digital Resin Quartz 200m Watch w/ Tin
Delivered prices include shipping as eBay quoted it to a US address on Oct 5, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Snapshot
Checked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 5, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
Used$71.35est. delivered
$65.00 + $6.35 shipping
Buy It Now$65.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Good buy
Gray, with tin. Not titled tested. Ships from the US.
Seller: Seller on eBay
Check feedback on the listing
Used$86.82est. delivered
$80.00 + $6.82 shipping
Buy It Now$80.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Good buy
Black, with tin. Ships from the US.
Seller: Seller on eBay
Check feedback on the listing
Used$80.00delivered
$80.00 · free shipping
Buy It Now$80.00
This seller takes offers, and many sellers accept less than the asking price.
Fine if you might miss it? Send an offer first. Someone else can still buy it while you wait for a reply.
Want it for sure? Use Buy It Now.
Our take
Titled GA2100-1ADR but called all black. Check the photos for which you'd get.
Seller: Seller on eBay
Check feedback on the listing
Used$142.22est. delivered
$112.22 + $30.00 shipping
Buy It Now$112.22
Our take
Black, from Japan. $30 shipping.
Seller: Seller on eBay
Check feedback on the listing
Used$147.25est. delivered
$117.25 + $30.00 shipping
Buy It Now$117.25
Our take
No version or condition given. $30 shipping from Japan.
Seller: Seller on eBay
Check feedback on the listing
Used$153.29est. delivered
$123.29 + $30.00 shipping
Buy It Now$123.29
Our take
Japan-market GA-2100RGB-1AJF. $30 shipping from Japan.
Seller: Seller on eBay
Check feedback on the listing
Used$254.71est. delivered
$194.71 + $60.00 shipping
Buy It Now$194.71
Our take
Special GA-2100SRS version, graded A by the seller. $60 shipping from Japan.
Seller: Seller on eBay
Check feedback on the listing
Used$355.86est. delivered
$295.86 + $60.00 shipping
Buy It Now$295.86
Priced high
About $175 over the band, with $60 shipping from Japan.
Seller: Seller on eBay
Check feedback on the listing
Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 5, 2026.
See every listing on eBay ↗eBay searchA fresh strap, a set of spring bars and a spring-bar tool are the cheap part of making an old Casio G-Shock GA-2100 wearable again. This searches Amazon for the usual kit.
Search straps & tools ↗Amazon search
Casio · G-Shock Round
G-Shockref DW-6900-1V
$100–$230 typical ask
Casio · G-Shock Square
G-Shockref DW-5600E-1V
$110–$160 typical ask
Casio · G-Shock Mudman
G-Shockref G-9000-1
$100–$220 typical ask