The 44 mm U-Boat Darkmoon Aquamarine pairs a matching silicone strap with a light blue dial immersed in oil.
The oil-filled dial
The light blue metal dial stands out against the black case. A small air bubble drifts across the dial as your wrist moves. Oil around the dial adds visual depth and makes the domed sapphire crystal above it seem to disappear.
The Swiss quartz movement sits in the same oil bath as the dial. The bubble is there by design, leaving room for the oil to expand and contract as the temperature changes. When the watch is off your wrist, U-Boat specifies a temperature range of 32–140°F (0–60°C).
Rooted in a 1942 naval design
The left-side crown comes from Ilvo Fontana’s 1942 plans for an Italian Navy watch that was never built. His grandson Italo revived the design in Lucca. On the Darkmoon, the crown screws down.
The details
The 44 mm case is 316L stainless steel with a black PVD finish, 17 mm thick, and water-resistant to 50 meters. The Locking Ring System on the back gives access to the battery.
The blue silicone strap closes with a steel pin buckle finished in black PVD. The watch is made in Italy.
The bubble is an intentional part of the oil-filled construction. It leaves room for the oil to change volume with temperature and moves as the watch changes position.
The Locking Ring System has a compartment for battery replacement. Oil adjustment uses a separate service opening reserved for U-Boat’s specialized technicians.
Keep it within U-Boat’s stated 0–60 °C range, away from prolonged direct sunlight, heat sources, and large temperature changes.
Yes, we are an Official U-Boat Authorised Dealer, and an authorised dealer for every brand we carry.
With over 15 years in the luxury market, we guarantee the authenticity and quality of every piece we sell.
Your order arrives brand new in its original U-Boat packaging, with all official documentation and the U-Boat warranty card, stamped and dated by us.
The warranty covers manufacturing defects. It doesn't cover normal wear and tear or accidental damage — and on watches, it doesn't cover straps, bracelets, or batteries.
Questions about a specific piece? Our specialists are happy to help. [Contact our team →]
Questions about a specific piece? Our specialists are happy to help.
Yes — free DHL Express shipping on all UK orders of £400 or more.
Every order ships with a tracking number, so you can follow your package every step of the way. Shipments are fully insured and delivered by DHL Express with signature required.
Most in-stock orders arrive within 1-2 working days of dispatch.
No — the price you see at checkout is the price you pay.
Our prices include VAT, and nothing is added beyond the delivery charge shown.
DHL will never ask you for a payment on delivery, and no surprise invoice arrives afterward.
No handling charges, no processing fees, nothing added at the door.
We accept all major credit and debit cards, Apple Pay, Google Pay, PayPal, and bank transfer.
Every transaction is fully encrypted, and we never store your card details.
Paying in instalments. Choose PayPal at checkout and you may be offered the option to spread the cost, including interest-free plans on qualifying orders. Plans, terms and eligibility are set by PayPal and shown before you confirm, with no obligation.
Paying by wire, or buying more than one piece? [Contact our team →] and we'll take care of you personally.
You'll find availability on every product page, right above the Add to Cart button. Here's what each status means:
"Dispatched next working day" or "Only 1 left" — the piece is in our warehouse and leaves the working day after you order.
"Dispatched within X working days" — the piece is held at our secondary warehouse. We allow a few days to inspect and authenticate it before dispatch.
"Check delivery date" — the piece is available to order, but we confirm the exact date with the brand. As soon as you order, we contact the manufacturer and email you an estimated date.
Need something by a specific date? Tell us and we'll check before you buy. [Contact our team →]
You have 30 days from delivery to return your order.
How returns work. Just let us know and we'll email you a prepaid DHL Express return label — you never have to arrange a shipment or pay anything up front. The return cost is deducted from your refund. If the piece arrived damaged or wasn't what you ordered, the return is on us.
Your refund options.
To qualify for a full refund, the piece must:
Not sure whether something qualifies? Ask us before you ship it back — we'll tell you straight. Contact our team.
Our specialists are here before and after you buy — no pressure, no obligation. Authorised dealer, official warranty, and guaranteed authenticity on every piece.

