CMK-100TD-1A Casio's £390 titanium field automatic

What is new about the Casio CMK-100?

Casio announced the CMK-100 on 29 October 2026, calling it "a lightweight mechanical timepiece with excellent readability". It sits under a new CASIO AUTOMATIC label and takes the shape of a classic field watch: a round titanium case, a flat-topped bezel, big Arabic numerals and a date at three. There are five versions. This one, the CMK-100TD-1A, is the flagship, with a black dial and a matching solid titanium bracelet. The others come on nylon or Italian leather straps, with black, grey or brown dials.

There is no older CMK to compare it with, so think of it as a fresh line rather than an update. Casio's UK site lists it as new for November 2026, and UK retailers such as Fraser Hart list the bracelet model at £390.

How big is it, and how will it wear?

On paper this is one of the most sensible sizes in Casio's catalogue. Casio quotes a 38 mm case, 44.7 mm lug to lug and 11.4 mm thick. The short lug to lug matters most: it means the bracelet starts curving down well inside the edge of most wrists, so the watch should sit flat even on a wrist of around 15 cm. Casio says the bracelet fits wrists from 150 to 205 mm.

Weight is the other headline. The bracelet model weighs 98 g, according to Casio, and the strap versions drop to 54 or 55 g. If you are used to a steel diver on a bracelet, that is a big difference you will notice at the end of the day.

The flip side: on a wrist over about 19 cm, a 38 mm field watch with a wide bezel may look small, and the dial opening is smaller than the case figure suggests.

What movement does it use, and how accurate is it?

Casio describes a "Made-in-Japan automatic movement with magnetic resistance". The operation manual is filed under module 5766. Casio's specification sheet lists 21 jewels, a beat rate of 21,600 vibrations per hour, hand winding, hacking seconds and a power reserve of approximately 42 hours.

The accuracy figure is the one to read twice. Casio quotes a mean daily rate of minus 20 to plus 40 seconds. That is a typical tolerance for an entry-level Japanese automatic, but it is a long way from the few seconds a month you get from a quartz Casio. If you take it off at the weekend, 42 hours will not carry you from Friday night to Monday morning.

How well is it built?

For the money, the specification sheet is strong:

• Case: titanium, with ion plating and a titanium carbide coating that Casio says improves abrasion resistance.
• Crystal: sapphire.
• Water resistance: 100 m (10 bar), with a screw-lock crown and a screw-lock case back.
• Dial: a stamped, finely textured black surface, with numerals printed in several layers of luminous paint so they stand slightly proud.
• Bracelet: solid titanium with a one-touch three-fold clasp.

Casio notes one quirk: because the case back screws in, the logo and lettering on it may not line up neatly with the dial. The case back is solid, so you will not see the movement.

Is it good value against its rivals?

At a £390 RRP, the CMK-100TD-1A lands in the middle of the affordable field automatic crowd. Two close rivals already on WhichWatch are the Seiko 5 Sports Field HDB009K1 at £350 RRP and the Timex Expedition Pioneer TW2Y87400 at £380 RRP. Both are steel. The Casio is the only one of the three in titanium, which is why it is so much lighter, and it pairs that with sapphire and screw-down sealing.

If you do not need the bracelet, the nylon and leather versions cost less and weigh barely half as much, which makes them worth a look as a lighter summer option. The titanium bracelet is what you pay the extra for here, and it is the version that best shows off the case material.

What is the catch?

Three things. First, accuracy: minus 20 to plus 40 seconds a day could mean several minutes of drift a week at the edge of the spec, so expect to reset it regularly. Second, the movement is a Casio module rather than a widely known calibre, so long-term servicing is an unknown until owners report back. Third, it is simply too new for real owner feedback; the watch reaches UK shops this month, and nobody has worn one for long yet.

None of that is unusual at this price. What is unusual is getting titanium, sapphire, 100 m and a 38 mm case from a brand most people know for digital watches.

“Titanium, sapphire and a 38 mm case, from a brand most people know for digital watches.”