Casio F-91W vs the MDV106 Dive Watch: Budget vs Step-Up
One's under ten bucks and legendary for it. The other costs more but does a lot more. Here's how to actually decide.
The short answer
If you need a cheap watch for everyday life and keep it out of the pool, buy the Casio F91W Series Digital Watch ($21.92, 4.6โ from 39,275 ratings). If you'll be in a pool, lake or ocean regularly, buy the Casio MDV106 Series Analog Dive Watch ($66.26, 4.7โ from 31,991 ratings). Prices are from our last check on 23 July 2026, and the difference is $44.34.
Bare-bones simplicity versus built for abuse
The F91W is about as minimal as a watch gets: a digital display with a stopwatch, a daily alarm and an auto-calendar. It's the watch you forget you're wearing. Our listing's drawback is that it has no reliable backlight for reading in the dark.
The MDV106 is a proper analog watch with a rotating unidirectional bezel and a stainless steel case and band. It lists 200m water resistance, and our note is that it's heavier than a typical digital watch.
Water resistance is the real dividing line
The F91W lists 30m water resistance. In practice that means splashes, rain and handwashing, not swimming. People do swim in them and sometimes get away with it, but it isn't what the rating covers.
The MDV106's 200m rating is the one to look for if you swim or snorkel. If water sports are part of your life, that rating is the reason to buy it. As with any dive watch, follow the maker's guidance for your specific activity.
The F91W is about as minimal as a watch gets: a digital display with a stopwatch, a daily alarm and an auto-calendar.
Which one to buy
If you want the cheapest possible daily watch and need nothing beyond a shower, the F91W is one of the best values in watches. If you're near a pool, lake or ocean regularly, spend the extra on the MDV106, so you use the capability instead of babying a watch that can't take it.
The MDV106 also doubles as a good-looking steel everyday watch, which the F91W is not. If you want one watch for everything, that's a point in its favour.
Compare
| Product | Brand | Price* | Rating | Best For | |
|---|---|---|---|---|---|
 Casio F91W Series Digital Watch |
Casio | $21.92 | โ 4.6 (39,275) | Everyday casual wear | Buy |
 Casio MDV106 Series Analog Dive Watch |
Casio | $66.26 | โ 4.7 (31,991) | Dive-style everyday watch | Buy |
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FAQs
Can I swim laps in the Casio F-91W?
It's not recommended. The F91W lists 30m water resistance, which covers splashes, not swimming.
Is the MDV106 a real dive watch or just styled like one?
Our listing describes 200m water resistance and a rotating unidirectional bezel, which are the features of a dive watch. For serious diving, follow the maker's guidance.
Does the Casio F91W have a backlight?
Our listing notes it has no reliable backlight for reading in the dark.
Why is the MDV106 so much more expensive?
You're paying for 200m water resistance, a steel case and band and a rotating bezel. It costs $44.34 more than the F91W at our last check.
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