Pictured from our pre-owned inventory: Blancpain Bathyscaphe Quantième Complet Phases de Lune 5054-1210-98S. This is the titanium-bracelet configuration; check the listing for current availability and condition.
The Blancpain Fifty Fathoms Bathyscaphe Quantième Complet Phases de Lune is for the collector who wants a sports watch without giving up the pleasure of a traditional calendar display. The titanium reference 5054-1210-98S combines day, date, month, and moonphase indications with a 43 mm case, automatic calibre 6654.P.4, and a manufacturer-stated water resistance of 30 bar (Blancpain specifications).
That combination is the reason to consider it. Rather than choosing between a simple diver and a dress-oriented calendar watch, you can explore a model that deliberately brings those two ideas together.
Understanding the complete calendar and moonphase
“Quantième Complet” means complete calendar: the day and month appear in apertures, while a central hand indicates the date (Blancpain’s complication guide). “Phases de Lune” refers to the moonphase display, which is included alongside the calendar on this Bathyscaphe (Blancpain’s model description).
Do not confuse “complete” with “perpetual.” A complete calendar does not account for different month lengths and needs correcting at the end of the five months with fewer than 31 days, assuming it has remained running and correctly set (Blancpain’s calendar explanation).
Think about whether you will enjoy that interaction. If you rotate several watches, ask for a demonstration of the setting procedure before deciding that a calendar is a convenient addition to your routine.
A closer look at the titanium 5054-1210-98S
The pictured reference is a useful starting point because its case and bracelet specifications are clearly documented by Blancpain. These are the figures to use when evaluating this configuration, not every Bathyscaphe carrying a calendar:
- Case: Titanium, 43 mm in diameter and 13.40 mm thick (Blancpain).
- Bracelet: Satin-brushed titanium with a folding clasp (Blancpain).
- Movement: Automatic calibre 6654.P.4, operating at 4 Hz, with a silicon balance spring (Blancpain).
- Power reserve: 72 hours according to the manufacturer (Blancpain).
- Water resistance: A published rating of 30 bar (Blancpain).
I would pay as much attention to the 13.40 mm thickness and bracelet fit as to the diameter. Ask how the watch sits from the side, how the clasp feels, and whether the bracelet can be sized comfortably for your wrist.
The ceramic version is not an identical specification
Blancpain lists the blue-dial ceramic-bracelet reference 5054-0140-01S at 43.60 mm in diameter and 13.40 mm thick, with a ceramic case and bracelet, the same named calibre 6654.P.4, a 72-hour power reserve, and 30-bar water resistance (Blancpain’s ceramic reference page). That 43.60 mm figure is a good reminder not to copy the titanium watch’s 43 mm specification into every listing.
Compare the complete watch rather than choosing a material in isolation. The dial, bracelet, clasp, proportions, and condition all need to work together for you.
When an individual listing describes a bracelet upgrade or a changed strap, ask what was supplied originally and what is included now. A reference page is useful for factory specifications, but it does not prove the accessory history of a pre-owned example.
Sports-watch ratings do not replace condition checks
A published water-resistance rating should not be treated as evidence of the present condition of a pre-owned watch’s seals. Blancpain recommends regular water-resistance checks and notes that an accidental shock can affect water resistance.
If water use matters to you, ask for recent testing and reference-specific operating guidance. Do not improvise with the crown or calendar controls based on the appearance of the case or a general discussion of dive watches.
The same approach applies to the calendar. Blancpain identifies the 6654.P.4 as a secured movement, but its product page is not a substitute for a full operating manual. Request the instructions for the exact watch and follow them.
What to ask before buying pre-owned
The best questions help you understand both the watch and the experience of owning it. I would start with these:
- Reference and configuration: Confirm the full reference, case material, fitted bracelet or strap, and included accessories.
- Calendar performance: Ask for a demonstration of the day, date, month, and moonphase adjustments using the correct procedure.
- Condition: Review close photographs of the case, bezel, crystal, clasp, and bracelet. Ask for an explanation of marks or repairs rather than guessing from a single photograph.
- Ownership history: Request service records where available and clarify the seller’s warranty and return terms.
For broader context, our Bathyscaphe collection article looks at the model family. This guide is specifically about deciding whether the complete-calendar version earns its place in your collection.
Would the Villeret suit you better?
If your main attraction is the calendar and you prefer a less sports-oriented appearance, compare this watch with the Villeret Quantième Complet. Start with the clothes, activities, and occasions you want the next watch to suit.
I would choose the Bathyscaphe direction when the contrast itself is the appeal: a calendar you can study and enjoy within a watch that looks at home in a casual rotation. I would not choose it merely because it offers more indications than a simpler watch.
Common questions
Is it an annual calendar?
No. Blancpain describes it as a complete calendar, which has a different correction schedule from an annual calendar (Blancpain’s explanation). Make that distinction part of your buying decision.
Are the titanium and ceramic versions the same size?
Not for the two references discussed here: Blancpain lists 43 mm for 5054-1210-98S and 43.60 mm for 5054-0140-01S. Check the specific reference rather than relying on a family-wide size claim.
Choose your Bathyscaphe with a clear brief
Tell me which dial and material you prefer, your wrist size, and whether a bracelet is essential. Start a Blancpain sourcing conversation with Pucks & Timepieces, and we can compare the right configurations for your budget and routine.
