Yes. The Seiko Prospex Marinemaster SBDX017, widely known as the MM300, was discontinued in 2018. That makes it a discontinued-watch purchase—not proof that examples are scarce, that prices will rise, or that you should buy one quickly. If you are considering one, compare its condition, completeness, service history, and return protections with the SBDX023 successor and current local alternatives.
When was the Seiko SBDX017 discontinued?
Fratello reported on July 5, 2018, that Seiko had told the publication earlier that year the Marinemaster 300 SBDX017 would be discontinued, and that it had by then left production. This is Fratello’s account of what Seiko told it, not a direct quotation from a named Seiko spokesperson or an official discontinuation notice. A Japanese authorized retailer, Prive Ishikawa, wrote on November 9, 2018, that SBDX017 production had ended and identified the SBDX023, released that day, as its successor.
Discontinued means it is no longer in regular production. New-old-stock and pre-owned examples may still appear for sale, but current inventory and market prices have not been established here. The phrase “get it while you still can” should not be read as evidence of verified scarcity or a forecast of future value.
What is the SBDX017?
The SBDX017 is a Prospex Marinemaster 300 diver and a lightly updated version of the earlier SBDX001 MM300, according to Fratello’s 2018 review. Fratello describes a 44 mm stainless-steel case, automatic Seiko 8L35 movement with date, Hardlex crystal, DiaShield treatment, revised Lumibrite, and a Prospex mark on the crown while the dial retained Marinemaster branding. These are details from a specialist review, rather than a current official SBDX017 specification page.
#1 Best Overall
- CRAFTER BLUE CB03 20mm curved end watch strap replacement watch band for Seiko MM300
- 20mm rubber watch strap compatible with Seiko MarineMaster SBDX001, SBDX003, SBDX005, SBDX017, SBDX021 (SLA019J1) and SBDX023 (SLA021J1), SBDX025, SLA023J1
- Lug width: 20mm; Buckle size: 18mm; Note: Buckle is NOT included, please use your original buckle.
- The NBR CRAFTER BLUE rubber strap is made of pure vulcanized rubber which has superior strength and more resistant than natural rubber to oils and acids
- Overall Length: 90mm + 55mm (Strap length:145mm / 5.71"); Thickness: Approx. 4.5mm - 3.5mm; Spring bar hole dia.: 2.50mm
The reviewed watch arrived with a steel bracelet and waffle-style rubber strap. That does not guarantee either accessory is included with every example; check the actual listing and sale documents.
SBDX017 vs. SBDX023: what changed?
The SBDX023 is identified as the SBDX017’s successor by Prive Ishikawa. Seiko’s official Japanese specification page documents the successor’s specifications below. Do not assume the models are identical or that the SBDX023 is the right replacement for every buyer.
Rank #2
- CRAFTER BLUE CB03 20mm curved end watch strap replacement watch band for Seiko MM300
- 20mm rubber watch strap compatible with Seiko MarineMaster SBDX001, SBDX003, SBDX005, SBDX017, SBDX021 (SLA019J1) and SBDX023 (SLA021J1), SBDX025, SLA023J1
- Lug width: 20mm; Buckle size: 18mm; Note: Buckle is NOT included, please use your original buckle.
- The NBR CRAFTER BLUE rubber strap is made of pure vulcanized rubber which has superior strength and more resistant than natural rubber to oils and acids
- Overall Length: 90mm + 55mm (Strap length:145mm / 5.71"); Thickness: Approx. 4.5mm - 3.5mm; Spring bar hole dia.: 2.50mm
| Feature | SBDX017 | SBDX023 |
|---|---|---|
| Case width | 44 mm, as described in Fratello’s 2018 review. | 44.3 mm, according to Seiko’s official Japanese specification page. |
| Crystal and bezel | Hardlex crystal; bezel material not stated in the cited SBDX017 review. | Sapphire crystal and ceramic bezel, per Seiko’s official Japanese specification page. |
| Movement | Automatic Seiko 8L35 with date, according to Fratello’s 2018 review; power reserve not stated there. | Automatic 8L35; approximately 50-hour power reserve, per Seiko’s official Japanese specification page. |
| Water-resistance category | Not stated in the cited SBDX017 review. | 300 m saturation-diving water resistance, per Seiko’s official Japanese specification page. |
| Other documented details | DiaShield treatment, revised Lumibrite, Prospex crown mark, and Marinemaster dial branding, per Fratello’s 2018 review. | DiaShield coating and one-piece case construction, per Seiko’s official Japanese specification page. |
The sources do not establish comparable thickness, weight, service condition, or current local price for these watches. Check official specifications for the exact reference and region, and assess an individual pre-owned watch on its own condition rather than inferring fit or value from case width alone.
Should you buy an SBDX017 while examples remain?
Consider it if you specifically want the SBDX017’s documented design and are comfortable evaluating a discontinued mechanical watch. Do not treat discontinuation by itself as a reason to stretch your budget: the available evidence does not establish remaining supply, current prices, or resale-price trends.
Rank #3
- DAY/DATE CALENDAR: stay organized with the convenient day/date calendar displayed on the beautiful blue dial
- STURDY STAINLESS STEEL CASE: designed for durability, this men's watch features a stainless steel watch case that can withstand everyday wear and tear SEIKO QUALITY: handcrafted timepieces for every occasion
- CLASSIC BROWN LEATHER STRAP: the combined sophistication and versatility of a supple leather watch band make these the perfect men’s watches for any occasion
- 50M WATER RESISTANT: whether you're washing your hands or snorkeling off the coast, these men's wrist watches are water-resistant up to 50 meters, providing peace of mind in any situation
- SMOOTH AUTOMATIC MOVEMENT: our self-winding automatic watches for men deliver precise and smooth movement, ensuring accurate timekeeping LUMINOUS HANDS AND MARKERS: even in low light conditions, the luminous hands and markers ensure that you can read the dial indicator
Before paying, work through the listing and seller details:
- Confirm the reference. Ask to see the case markings and paperwork identifying the watch as SBDX017; compare them with the listing.
- Assess condition. Review clear photographs and ask about damage, prior polishing, operation, and any known repairs. For a costly used mechanical watch, a qualified pre-purchase inspection may help you understand its condition.
- Verify what is included. Confirm whether the sale includes the bracelet, strap, box, papers, or other items, and whether those items are original to that particular watch.
- Ask for service records. Request dates, work performed, and supporting documentation. No model-specific service interval is established here.
- Read the protections. Check the seller’s return window, warranty scope, and who pays for return shipping or inspection if the watch is not as described.
- Compare the full cost. Use the seller’s actual price and any inspection or service costs you anticipate; no current SBDX017 market price is established here.
What alternatives should you compare?
The SBDX023 is the documented successor, but the current Marinemaster range is broader than one replacement model. Seiko’s UK lineup page, accessed in 2026, lists HBF001, HBF002, SJE099, SJE101, SJE117, SJE119, SLA077, and SLA079, and describes Marinemaster as its flagship diver-watch series. That is a regional lineup snapshot, not a guarantee of current availability elsewhere. Check Seiko’s site for your country or an authorized local retailer for live models and prices.
Rank #4
- STUNNING BLUE DIAL: this automatic men's watch features a deep blue, pressed pattern and gloss finish surrounded by a stainless steel watch case
- AUTOMATIC: these self-winding, automatic men's watches are powered by your movement, with a power reserve of 41 hours
- STAINLESS STEEL: features a durable stainless steel watch case and bracelet with see through caseback
- WATER-RESISTANT: these men's wrist watches are water-resistant down to 50 meters
- 4R35 CALIBER: equipped with the reliable caliber 4R35 automatic movement, this accurate men's watch keeps precise time
When weighing an SBDX017 against an SBDX023 or another current Marinemaster, compare the points that affect both daily use and financial risk:
Quick Recap
Best Value
- RACING-INSPIRED DIAL: Silver and orange striped dial with luminous hands and a blue seconds hand ensures clear readability and bold style in watches for men.
- AUTOMATIC MOVEMENT: Powered by Caliber 4R36 with manual winding capability and 41-hour power reserve, a standout in men’s wrist watches.
- STAINLESS STEEL CASE: Durable 42.5mm stainless steel case with screwdown see-through caseback showcases classic mechanical precision.
- WATER RESISTANT: 100M (10 bar) water resistance makes this men’s watch reliable for everyday wear and active lifestyles.
- UNIDIRECTIONAL BEZEL: Light silver rotating bezel paired with striped nylon strap for comfort, secure fit, and sporty aesthetic among luxury watches for men.
- Case width and thickness, and how the watch fits your wrist.
- Crystal and bezel materials, movement, published power reserve, and stated water-resistance category.
- Dial and crown branding, if the SBDX017’s specific presentation is part of its appeal.
- Condition, included accessories, documented service history, and seller warranty and return terms.
- The actual local price for each specific reference, rather than an assumed premium for a discontinued model.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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