The short answer

The Omega Seamaster Aqua Terra 150M 41mm is a 41mm sports watch with 150 metres of water resistance and a Co-Axial Master Chronometer automatic movement. If you want one, buy the genuine watch from an authorized dealer or a vetted pre-owned seller, and verify the reference number, the movement, and the certification card before money changes hands.

This guide covers the genuine watch only. It does not cover replica or counterfeit versions, and it will not help you buy one. Selling or importing counterfeit trademarked goods is illegal in the United States and most other markets, and the specifications claimed for replicas cannot be verified by any independent party.

Specs at a glance

  • Case: 41mm diameter, roughly 13.2mm thick, 20mm lug width
  • Water resistance: 150 metres (15 bar)
  • Movement: Omega Co-Axial Master Chronometer calibre 8900, automatic, 60-hour power reserve
  • Magnetic resistance: 15,000 gauss
  • Crystal: domed sapphire front, sapphire caseback
  • Dial: teak pattern with horizontal lines on current references
  • Bracelet or strap: steel bracelet with butterfly clasp and micro-adjust, rubber, or leather

Before you start

  • A budget. Steel models on a bracelet generally list in the low-to-mid $6,000 range; two-tone and gold versions cost more. Confirm current pricing with an authorized dealer.
  • The exact reference number you want. The 11-digit string encodes case material, dial color, and bracelet type.
  • A written return window if you buy pre-owned.
  • Access to a watchmaker who can pressure-test a case and read a movement.

How to check a 41mm Aqua Terra before you buy

  1. Match the reference number on the caseback to the number printed on the warranty card. A steel 41mm on a bracelet begins with 220.10.
  2. Look through the sapphire caseback and find the calibre number 8900 engraved on the rotor.
  3. Read the Master Chronometer card. Omega ships a card with the METAS test results, and its serial must match the caseback serial.
  4. Measure the case with calipers at the 9 and 3 o'clock points, excluding the crown. You should read 41mm, with 20mm lugs.
  5. Confirm the dial pattern. Current 41mm references use horizontal teak lines; older references use vertical lines.
  6. Ask for service history on any pre-owned example. Receipts from an Omega service center or an extract from the Omega archives are the strongest proof.
  7. Take the watch to a watchmaker and have the case pressure-tested and the movement verified before the return window closes.
  8. Pay by a method that carries buyer protection, and keep the receipt and all correspondence.

Signs something is wrong

  • Serial numbers that do not match between the case and the card.
  • A rotor with no calibre number, or a number that does not match the reference.
  • A seller who refuses photos of the movement or blocks an inspection.
  • A price far below market for a watch described as new with box and papers.

What it costs to own

Budget for a service roughly every five to eight years. Omega recommends service intervals based on wear, and a full service on a Master Chronometer movement is not cheap. Factor that into the purchase price, especially on a watch with unknown history.