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Rotary Seamatic 300 42mm Mens Watch Green
Ref. RGB05430/78
Sits in Rotary’s upper tier here — more premium than three quarters of the Rotary watches we list, which start at £76.
Price range £76 to £349 across 160 Rotary watches in stock.Rotary's Seamatic line exists to make a serious dive specification accessible without theatrical branding or inflated proportions. The 300-metre rating here is genuine tool-watch territory, and the 14mm case keeps it flatter than most watches rated anywhere near that depth — flat enough to clear a cuff, which dive-capable watches at this rating rarely manage. The green dial sits behind a black ceramic bezel, a pairing that reads as purposeful rather than decorative: the contrast aids quick elapsed-time readings under poor visibility. The Miyota 8215 inside is a workhorse calibre — robust, widely serviced, with a 40-hour reserve — which suits a watch likely to see actual use rather than a drawer.
- Reference
- RGB05430/78
- Brand
- Rotary
- Case size
- 42mm
- Case material
- Stainless steel
- Case shape
- Round
- Dial
- Green
- Crystal
- Sapphire
- Movement
- Automatic
- Calibre
- Miyota 8215
- Functions
- Date
- Water resistance
- 300m
- Bracelet / strap
- Stainless steel bracelet
- Strap colour
- Silver
- Lume
- Luminous
- Retailer
- Goldsmiths
Additional specifications
- Power reserve
- 40 hours
Learn more about Rotary
Moise Dreyfuss started Rotary in La Chaux-de-Fonds in 1895. Within a generation his sons Georges and Sylvain had opened a London office and begun exporting to Britain, which turned out to be the decision that defined the company: Britain became, and remains, Rotary's most important market.
The winged wheel logo arrived in 1925 and has barely changed since. It became familiar enough in British high streets that the brand is widely taken for British, despite the Swiss origin.
Rotary supplied watches to the British Army, and the wartime and post-war association gave it a foothold in a market where an affordable, dependable Swiss watch was exactly what most buyers wanted.
The family held the company for over a century, making it for a long time the oldest family-owned Swiss watchmaker still trading. Ownership passed to Hong Kong's Citychamp in 2014, and in February 2025 to the UK's Peers Hardy Group.
The modern range sits at the accessible end — quartz and automatic dress watches, divers and chronographs, with the Henley, Windsor and Legacy lines carrying the collection.
- 1895
- Founded in La Chaux-de-Fonds by Moise Dreyfuss.
- 1920s
- Georges and Sylvain Dreyfuss begin exporting to Britain.
- 1925
- The winged wheel logo is introduced.
- 2014
- Acquired by Citychamp after more than a century in family hands.
- 2025
- Bought by the UK's Peers Hardy Group.
Also in 6 collections
This watch appears in Back in Stock (3,225), Stainless Steel Watches (3,084), Automatic Watches (1,759), Sports Watches (794), Dive Watches (567) and Green Dial Watches (416).
Manufacturer’s guarantee
What the specifications mean
A mechanical watch built to be worn hard and got wet.
Strengths
- 300m water resistance, rated for actual diving
- Sapphire crystal, which resists scratching
- Luminous hands and markers for low light
- One of Rotary's more premium watches
Worth knowing
- 40-hour reserve means winding it after a day off
Rotary Seamatic 300 alternatives
Watches from other brands at a similar price, style and size, so you can see what else your budget can buy.
| Specification | RGB05430/78 | R8821108039 | SRPD55K1 |
|---|---|---|---|
| Price | £224 | £229 | £230 |
| Case size | 42mm | 42mm | 42.5mm |
| Water resistance | 300m | 100m | 100m |
| Movement | Automatic | Automatic | Automatic |
| Strap | Stainless steel bracelet | Leather strap | Stainless steel bracelet |
| Power reserve | 40 hours | — | — |
| This watch |
|
|
Your new watch
Frequently asked questions, and things you should know about this watch
Can I swim with it?
Yes. At 300m it is rated for swimming, snorkelling and recreational diving.
Water resistance explainedWill the glass scratch?
Unlikely. Sapphire is second only to diamond in hardness and shrugs off everyday marking.
Sapphire, mineral and acrylic comparedDoes it need a battery?
No. It is automatic — the motion of your wrist winds it, and there is no cell to replace.
Quartz, automatic and solar comparedHow long does it run for when it's not worn?
About 40 hours fully wound — enough to survive a night off the wrist, but not a full weekend.
Is it a men's or women's watch?
Listed as men's.
Cheapest place to buy
Goldsmiths is the only UK retailer we track stocking this reference, so there is nothing to compare it against today.
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