CITIZEN BY1030-09A ECO-DRIVE MEN WATCH
BY1030-09A
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- 20% off in cart
- 3 Years Warranty
The Citizen BY1030-09A stacks five serious complications onto one Eco-Drive movement: a moon phase display, perpetual calendar, world time across 24 zones, global radio-controlled timekeeping, and a power reserve level indicator. All of it runs from Citizen's Caliber H874 — powered entirely by light, with no battery, ever.
A white dial with a subtle sunburst finish carries three sub-dials for moon phase, 24-hour time and day, plus a date window. Index hour markers and silver-tone hands keep it legible despite the layered complications, set in a 42mm stainless steel case at 10.7mm thick, finished on a blue calf leather strap with a deployment clasp.
Sapphire crystal protects the dial and Duratect coating adds scratch resistance to the case. The watch is water resistant to 100 metres and weighs 82 grams. A full charge holds for approximately 6 months in the dark.
At a Glance
- BrandCitizen
- CollectionEco-Drive
- MovementCaliber H874 Eco-Drive
- Case Size42mm
- Thickness10.7mm
- Weight82g
- DialWhite, Sunray
- ComplicationsMoon Phase, Perpetual Calendar, World Time
- TimekeepingGlobal Radio-Controlled
- Case FinishSilver-Tone, Duratect
- GlassSapphire Crystal
- StrapBlue Calf Leather
Why You'll Love It
- Five complications on one dial: moon phase, perpetual calendar, world time, radio-controlled timekeeping and a power reserve indicator — a genuine step up from a standard three-hand or day-date watch.
- Global radio-controlled reception means the watch syncs its own time from atomic clock signals covering Europe, the USA, China and Japan — no manual correction needed for accuracy.
- A perpetual calendar accounts for varying month lengths and leap years automatically, so the date stays correct without manual adjustment across the calendar year.
- The moon phase display switches between Northern and Southern Hemisphere views — a genuinely rare feature that also makes the watch relevant wherever you're wearing it.
- Eco-Drive means no battery, ever. A full charge holds for roughly 6 months with no light exposure at all, and the power reserve indicator lets you see your charge level at a glance.
- Sapphire crystal is meaningfully more scratch-resistant than the mineral glass used on Citizen's entry-level pieces, and Duratect coating adds further surface hardening to the case.
- A white sunburst dial with silver-tone hands and index markers keeps the layered complications legible rather than cluttered — a genuinely well-organised dial for how much it's doing.
- 100-metre water resistance gives real everyday margin against rain, splashes and handwashing, well beyond what a dress or complication watch typically needs.
Perfect For
- Complication Watch Collectors
- Eco-Drive & Solar Watch Fans
- Moon Phase Enthusiasts
- Frequent Travellers
- Office & Formal
- Milestone Gift
- Watch Enthusiast Gift
Key Features
- Citizen Eco-Drive Caliber H874 — light-powered movement, no battery required, holding a charge for approximately 6 months in full darkness once fully charged.
- Global Radio-Controlled timekeeping — receives time signals from atomic clocks covering Europe, the USA, China and Japan for automatic accuracy correction.
- Perpetual calendar — automatically accounts for varying month lengths and leap years.
- Moon phase display — automatic moon phase calculation with a switch between Northern and Southern Hemisphere views.
- World time in 24 time zones — track a second (or third) time zone from the dial.
- Power reserve level indicator — shows remaining charge at a glance.
- Summer Time ON/OFF function — for regions observing daylight saving.
- Insufficient Charge Warning and Overcharge Prevention — the watch manages and protects its own charge automatically.
- Sapphire crystal with Duratect coating — scratch-resistant glass and case surface.
- 42mm stainless steel case — 10.7mm thick, weighing 82 grams.
- Blue calf leather strap — deployment clasp.
- 100-metre water resistance (10 BAR) — rated for handwashing, rain and everyday splashes.
Technical Specifications
The Citizen BY1030-09A is a 42mm men's Eco-Drive watch powered by Caliber H874, combining global radio-controlled timekeeping with a perpetual calendar, moon phase display, 24-time-zone world time and a power reserve level indicator. The stainless steel case measures 10.7mm thick with sapphire crystal, Duratect surface coating and is water resistant to 100 metres. The white sunray dial carries index hour markers with sub-dials for moon phase, 24-hour and day display, plus a date window. It weighs 82 grams on a blue calf leather strap with a deployment clasp.
| Model Number | BY1030-09A |
| Case Material | Stainless Steel, Duratect Coated |
| Case Diameter | 42mm |
| Case Thickness | 10.7mm |
| Weight | 82g |
| Glass | Sapphire Crystal |
| Caseback | Solid |
| Water Resistance | 100 Metres (10 BAR) |
| Colour | White, Sunray |
| Markers | Index, Silver-Tone |
| Sub-Dials | Moon Phase, 24-Hour, Day |
| Display | Hours, Minutes, Seconds, Date, Day, Moon Phase |
| Material | Calf Leather |
| Colour | Blue |
| Clasp | Deployment |
| Caliber | Citizen H874 |
| Type | Eco-Drive (Light-Powered) |
| Timekeeping | Global Radio-Controlled |
| Calendar | Perpetual Calendar |
| Moon Phase | Automatic Calculation, N/S Hemisphere Switching |
| World Time | 24 Time Zones |
| Full Charge Reserve | Approx. 6 Months |
| Functions | Power Reserve Indicator, Summer Time ON/OFF, Insufficient Charge Warning, Overcharge Prevention |
Best Matched With
- Navy Suit
- White Dress Shirt
- Charcoal Overcoat
- Grey Wool Trousers
- Black Leather Belt
- Silver Cufflinks
Frequently Asked Questions
What does "global radio-controlled" mean?
The watch receives time signals from atomic clock transmitters covering Europe, the USA, China and Japan, and automatically corrects itself for perfect accuracy — no manual time-setting needed in areas with reception. Outside those coverage zones, it keeps time as a highly accurate quartz watch until the next signal is received.
What is a perpetual calendar?
A perpetual calendar automatically accounts for months of different lengths and leap years, so the date display stays correct without you ever needing to manually adjust it at month-end.
How does the moon phase display work?
A sub-dial shows the current phase of the moon, calculated automatically by the movement. It can also be switched between Northern and Southern Hemisphere views, since the moon phase appears mirrored depending on where you are in the world.
What is Eco-Drive?
Eco-Drive is Citizen's light-powered movement technology. A cell beneath the dial converts any light source — sunlight, a lamp, an overhead office light — into energy stored in a rechargeable cell, so the watch never needs a battery.
How long does the charge last if I stop wearing it?
Approximately 6 months from a full charge with no further light exposure. An Insufficient Charge Warning function alerts you before the reserve runs out, and the power reserve indicator on the dial lets you check your charge level at any time.
Can I use this to track a second time zone?
Yes. World time across 24 time zones is built into the movement, so you can reference another zone directly from the dial — useful for frequent travellers or anyone coordinating across regions.
Can I swim with this watch?
The case is rated to 100 metres, which comfortably covers handwashing, rain and everyday splashes. That said, the strap is calf leather — leather doesn't hold up well to sustained water exposure regardless of the case rating, so swimming and showering aren't recommended. Take it off before either.
Is Duratect the same as sapphire crystal?
No — they protect different parts of the watch. Sapphire crystal is the scratch-resistant glass over the dial. Duratect is Citizen's proprietary surface-hardening coating applied to the case itself, helping it resist everyday scuffs and scratches.
Will 42mm fit my wrist?
42mm runs slightly larger than the standard 40mm men's size and suits medium to larger wrists well. At 82 grams and 10.7mm thick, it carries genuine presence without feeling heavy given how many functions are packed in.
Is the strap adjustable?
Yes. The deployment clasp can be adjusted for fit, and City Chain can advise on strap sizing or replacement in-store if needed.
What warranty does this watch come with?
The BY1030-09A comes with a City Chain Singapore warranty when purchased from an authorised outlet. Keep your warranty card and proof of purchase — both are required when submitting the watch for service at any City Chain outlet.
Why Buy from City Chain Singapore
- Authorised Retailer 100% genuine Citizen product
- Warranty Included Covered on every purchase
- Free Shipping All orders within Singapore
- Strap Fitting Size it in-store
Extra $15 OFF with min. $200 spend
Use Code: FORYOU15
Extra $30 OFF with min. $400 spend
Use Code: FORYOU30
Caliber No.: H874
Movement: Eco-Drive (Light-Powered)
Maximum Run Time: Approx. 6 months (fully charged)
Functions:
24-Hour Display
Day & Date Display
Automatic Moon Phase Calculation
Double Moon Phase Display
Moon Phase Display Switching (Northern/Southern Hemisphere)
Global Radio-Controlled Timekeeping
Perpetual Calendar
Power Reserve Level Indicator
Summer Time ON/OFF
World Time (24 Time Zones)
Insufficient Charge Warning
Overcharge Prevention
Case Size: 42mm
Case Thickness: 10.7mm
Case Material: Stainless Steel
Glass: Sapphire Glass
Strap: Calf Leather Strap
Water Resistance: 100 metres
Weight: 82g
Delivery within Singapore
Order by 11AM
(Mon - Fri for faster processing)
Checkout options may vary depending on order value and eligibility.
• Free Speedpost Domestic Delivery — 1–2 business days
• Free DHL Domestic Delivery — next business day
• Express Delivery — S$30, order by 2PM
• Click & Collect — ready in 2–3 business days. Please wait for the collection confirmation email before visiting the store.
Weekend & Public Holiday Orders
Orders placed after the applicable cut-off time, on weekends, or on public holidays will be processed on the next business day. Delivery will take place on the next available business day based on the selected delivery service.
During peak periods, festive seasons, major launches or sale events, additional processing and delivery time may be required.
For online purchase, you can have bracelet or leather strap adjustments done at any City Chain store. Please bring along your warranty book for the service.
