Casio · ref F-91W-1 · 1989–present
The F-91W came out in June 1989 as the successor to the F-87W, and it's still in Casio's catalog. For years the internet said 1991. Wikipedia carried that date from 2009 until 2019, a BBC article repeated it, and it only got fixed after a news story traced the error. Ryusuke Moriai designed it as his first Casio watch, and he went on to design G-Shocks. Module 593 is stamped on the caseback and gives you a 1/100-second stopwatch, a daily alarm, an hourly chime and a calendar that counts every February as 28 days. Casio rates the CR2016 battery for about seven years. It weighs 21 grams and is only marked Water Resist, so treat it as splash-proof. Fakes are common even at this price. A used one makes sense for an early example with the old amber light, a boxed one, or a color you can't buy new.
Counterfeits are common and usually have cheaper plastic, narrow viewing angles, louder beeps and worse timekeeping. On genuine ones the resin strap eventually cracks near the case.
Buying guide
Buy from a US seller, where a used F-91W asks $19–42 delivered, and the $23 one titled tested working is our pick. There are about 150 listed, and the $20–130 band is that wide because Japan resellers list the same watch as a Cheap Casio for $60–115 plus $60 shipping. Fakes are common even at this price, so read module 593 on the steel caseback, ask for the CASIo test photo, look at the screen from an angle, and check the seller's feedback and return policy on the item page. Ask for a photo with the light on too, since an amber light means an older one and green the newer.
$19.33est. delivered
The lowest delivered F-91W here at $19, a military green one from a US seller. It isn't titled tested, so ask for the CASIo test photo and a look at the caseback before you buy.
CASIO F-91W Digital Watch. Military Green Water Resistant
$23.11est. delivered
Titled tested working, from a US seller, at $23 delivered, near the bottom of the band. Ask for the CASIo test photo anyway, since fakes turn up at this price too.
Casio F-91W digital watch Unisex Watch Tested Working
$31.98est. delivered
Titled new battery, at $32 delivered from the US, so it should be ready to wear. It's on a clear band, so check the photos if you want the stock black look.
Casio F-91W Clear Band Digital Watch New Battery 32MM 8" Resin Band
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$19.33est. delivered
$13.99 + $5.34 shipping
Buy It Now$13.99
Good buy
Military green. Not titled tested. Ships from the US.
Seller: Seller on eBay
Check feedback on the listing
Used$23.11est. delivered
$13.76 + $9.35 shipping
Buy It Now$13.76
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
Titled tested working. Ships from the US.
Seller: Seller on eBay
Check feedback on the listing
Used$31.98est. delivered
$24.99 + $6.99 shipping
Buy It Now$24.99
Good buy
Clear band, titled new battery.
Seller: Seller on eBay
Check feedback on the listing
Used$22.95delivered
$22.95 · free shipping
Buy It Now$22.95
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
Module 593 per the title. Free shipping from the US.
Seller: Seller on eBay
Check feedback on the listing
Used$35.00est. delivered
$30.00 + $5.00 shipping
Buy It Now$30.00
Our take
Green, module 593 per the title.
Seller: Seller on eBay
Check feedback on the listing
Used$35.93est. delivered
$30.00 + $5.93 shipping
Buy It Now$30.00
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
Gold and black, titled vintage. No word on running.
Seller: Seller on eBay
Check feedback on the listing
Used$125.94est. delivered
$65.94 + $60.00 shipping
Buy It Now$65.94
Our take
Japan reseller, $60 shipping on a $66 ask. US sellers ask $19–42 delivered.
Seller: Seller on eBay
Check feedback on the listing
Used$185.41est. delivered
$149.41 + $36.00 shipping
Buy It Now$149.41
Priced high
About $55 over the band, with $36 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 F-91W wearable again. This searches Amazon for the usual kit.
Search straps & tools ↗Amazon search
Casio · Casio Classic Digital
Digitalref A159W
$50–$100 typical ask
Casio · Casio Classic Digital
Digitalref A168WA-1
$65–$150 typical ask
Casio · Casio Classic Digital
Digitalref AE-1200WH-1A
$35–$55 typical ask