The DOXA SUB 300 returns to form with this 2020 iteration, carrying forward the original 1967 concept whilst incorporating contemporary precision standards. This particular reference, the 821.10.351.10, presents the iconic Professional orange dial configuration, the very colour that defined an entire generation of professional diving timepieces and earned legendary status alongside Jacques-Yves Cousteau’s expeditions aboard the Calypso.
Painted Precision and Luminescent Architecture
The orange dial of the SUB 300 Professional employs a painted surface treated with what DOXA refers to as an “iconic” finish: a glossy, opaque application that delivers exceptional saturation and visual impact. This construction differs fundamentally from contemporary sunray treatments, offering instead a dense, uniform colour field that references the original 1967 specification whilst maintaining stability under varying light conditions.
The dial architecture comprises painted indices executed in black with central applications of Super-LumiNova luminescent material. These rectangular hour markers sit proud against the orange surface, creating clear visual separation. The five-minute intervals receive particular emphasis through larger indices, whilst intermediate minute markers appear as refined hash marks along the outer minute track.
The handset follows DOXA’s inverted hierarchy. The minute hand dominates with its oversized proportions, a deliberate choice rooted in dive timing practicality, whilst the hour hand adopts smaller dimensions. Both hands carry generous quantities of Super-LumiNova, as does the seconds hand with its distinctive lollipop configuration. The date aperture occupies the three o’clock position, framed in black to maintain visual coherence.
Dial printing includes the DOXA wordmark and “automatic” designation at ten-thirty, balanced by “SUB 300 professional” text at four-thirty, an asymmetrical arrangement that achieves spatial equilibrium through diagonal opposition. The minute track encircles the dial perimeter, painted in white with black accents to ensure legibility during timed dive sequences. The date is present in a delimited cartouche and offers a good balance with the rest of the dial colour scheme.
The Movement: COSC-Certified ETA 2824-2 with DOXA Decoration
The SUB 300 Professional houses a Swiss SW200-1 automatic calibre that has undergone COSC (Contrôle Officiel Suisse des Chronomètres) chronometer certification. This workhorse movement delivers proven reliability through a 25-jewel construction beating at 28,800 vibrations per hour (4 Hz). It is widely used on the market having the advantage of high volumes and extended network of watchmakers able to fast and easy service it.
The movement’s architecture comprises a bidirectional winding rotor secured by a central screw to the barrel bridge, with the automatic winding system incorporating two reversing wheels. The balance wheel, positioned at twelve o’clock with a clockwise balance cock, generates considerable inertia, a characteristic that contributes to the calibre’s 42-hour power reserve specification. The Etachron-type regulator provides rate adjustment, whilst the anti-shock system protects critical components from impact.
COSC certification ensures the movement maintains chronometric performance within -4/+6 seconds per day deviation. This chronometer-grade variant employs an Anachron hairspring, Glucydur balance wheel, Incabloc anti-shock device, and red ruby pallet jewels. The movement features hacking seconds functionality and manual winding capability in addition to automatic operation.
DOXA applies proprietary decoration to the movement, distinguishing this calibre from standard ebauche specifications. The rotor carries DOXA engraving, whilst finishing extends across visible components. The movement measures 25.6mm in diameter by 4.6mm in thickness, a relatively slim profile that contributes to the watch’s overall case proportions.
316L Stainless Steel Construction and Engineered Proportions
The SUB 300 Professional case measures 42.5mm in diameter by 45mm lug-to-lug, with a thickness of 13.4mm including the domed sapphire crystal. This dimensional balance creates wearability across varying wrist sizes. The relatively short lug-to-lug measurement in particular prevents overhang on smaller wrists whilst the 42.5mm diameter maintains substantial presence.
Construction employs AISI 316L stainless steel throughout the case components. This marine-grade alloy offers exceptional corrosion resistance, critical for a timepiece rated to 300 metres (30 bar) water resistance. The case finishing combines brushed surfaces on top edges with polished sides, creating visual definition through contrasting textures. The crown sits recessed into the caseband at three o’clock, eliminating the need for crown guards whilst maintaining protection against impact.
The screw-down crown and screw-in caseback ensure water integrity to the specified 300-metre depth. Both components feature threading that engages the main case body, compressing gaskets to create sealed interfaces. The caseback carries factory engraving including the DOXA fish logo and technical specifications.
The sapphire crystal adopts a domed “box” configuration with anti-reflective treatment, deliberately echoing the curved plexiglass employed on original SUB 300 generations from 1967. This box crystal construction requires substantially greater sapphire volume than flat crystal alternatives, approximately double the material thickness, necessitating precision CNC machining to achieve the curved internal and external surfaces. The anti-reflective coating applies via vacuum deposition, where metal oxide materials (typically magnesium fluoride or silicon dioxide) are sputtered onto the crystal surface in controlled thickness to cancel reflected light waves through optical interference. This coating delivers improved dial legibility, particularly under challenging lighting conditions, though it introduces slight vulnerability to scratching compared to untreated sapphire.
The unidirectional rotating bezel constitutes a defining element of the SUB 300 design language. The bezel features DOXA’s patented dual-scale configuration: an outer ring displaying diving depths in metres (rendered in orange for the Professional variant) and an inner ring marking dive times in minutes (executed in black). This integrated no-decompression limit calculator derives from US Navy dive tables, enabling divers to determine safe bottom times at predetermined depths without requiring decompression stops during ascent.
The bezel construction employs stainless steel with 120 detents providing precise indexing, with each click representing 30 seconds of elapsed time. The teeth or serrations on the bezel edge facilitate manipulation whilst wearing diving gloves, with the edges raised and rigidly defined for positive grip. A Super-LumiNova pip at twelve o’clock on both the outer orange ring and inner black ring ensures orientation reference in low-visibility conditions.
Bracelet Integration and Deployment
The SUB 300 Professional on reference 821.10.351.10 ships with DOXA‘s signature “beads of rice” bracelet, a five-row link design featuring rounded, polished centre links flanked by brushed outer links. This bracelet style traces its lineage directly to the original 1967 SUB 300, establishing immediate visual continuity with vintage references.
The bracelet employs 316L stainless steel construction matching the case material, with 20mm lug width providing proportional integration. Individual links nest together in the characteristic beads of rice configuration, creating flexibility whilst maintaining structural integrity. The finishing alternates between high-polish on centre links and brushed treatment on outer links, generating visual texture through light reflection.
The folding clasp carries the embossed DOXA fish symbol and incorporates a diver’s extension mechanism. This butterfly extension deploys to accommodate wetsuit thickness, allowing rapid adjustment without tools. The clasp mechanism locks securely whilst permitting quick release when required, a practical consideration for professional diving applications. The bracel is comfortable and looks amazing.
Concluding Observations
The SUB 300 Professional reference 821.10.351.10 represents DOXA’s commitment to heritage-informed design executed with contemporary manufacturing standards. The watch delivers fundamental dive watch functionality: 300-metre water resistance, luminescent elements, timing bezel, through proven components including the COSC-certified calibre and 316L stainless steel case architecture.
The orange Professional dial variant maintains direct visual connection to the 1967 original, preserving the colour specification that defined the model’s identity within professional diving circles. The box sapphire crystal, domed to reference vintage plexiglass whilst offering scratch resistance, successfully bridges historical aesthetic with functional durability.
The watch is a fantastic tool and companion. During the entire test time I enjoyed it. I played with the bezel, I looked at it in various lights. It is comfortable and easy to wear. I thing DOXA is doing an excellent job and offers a compelling watch. It was not spared in our adventures in Normandie and I was happy that I decided for this model. The colours, the construction the robustness. A bit of fun in a serious tool watch.
At € 2.790 on the beads of rice bracelet, the SUB 300 Professional occupies a premium position within the current collection. The chronometer certification, proprietary movement decoration, and heritage bracelet construction justify this positioning, delivering tangible specifications rather than simply trading on historical association. This watch serves collectors seeking authentic vintage design language executed with reliable modern internals, a balance that DOXA navigates with particular competence through the SUB 300 Professional.
You can follow our vacation days with DOXA here:
In vacation… with DOXA
Visiting Avranches with DOXA
Visiting Mont Saint-Michel and Saint-Malo with DOXA
The Great Bunker Ouistreham and Merville Battery Museum with DOXA
Visiting Étretat and enjoying another face of Atlantic with DOXA SUB
You can read the review of the SUB 200T Aquamarine here: Review: DOXA SUB 200T Aquamarine
DOXA SUB 300 Professional Technical Specifications
Reference 821.10.351.10 – CHF 2’490.00 / EUR 2.790,00
Indications
- Hours, minutes, seconds, date
Movement
- Mechanical self-winding, 3 hands, COSC Certified Chronometer
- Power reserve: 42 hours
- Frequency: 28,800 vibrations per hour (4.0 Hz)
- 25 rubies – with DOXA decorations
Case
- Stainless steel – Diameter: 42.50 mm x 45.00 mm – Thickness 13.40 mm
- Crystal: Glass box sapphire
- Unidirectional bezel, lug width: 20 mm
- Stainless steel screw-in case back – Screw-down crown
- Water resistance: 300 meters, equivalent to 30 BAR, about 984 feet
Dial
- Painted indices highlighted with Super-LumiNova® luminescent material
- Hands highlighted with Super-LumiNova® luminescent material
- Painted outer minute track
Bracelet
- Choice of stainles steel “rice bead” bracelet with folding clasp,
- Exclusive “DOXA fish”, symbol with diver’s extension for quick adjustment to wetsuit
- Black rubber strap or tone-on-tone strap (to match dial color) with folding clasp, exclusive “DOXA fish” symbol, with diver’s extension for quick adjustment to wetsuit
