Quick answer

Omega does not make an Aqua Terra with 300m water resistance. The Aqua Terra line is rated 150m. The 300m rating belongs to the Seamaster Diver 300M. That model measured 41mm from 1993 to 2017 and moved to 42mm in 2018. A listing that says "Aqua Terra 300m 41mm" merges two different watches. Replicas of both exist, and both carry the same tells.

Genuine Aqua Terra 41mm specs

  • Case: 41mm steel, 13.2mm thick, 20mm lug width.
  • Water resistance: 150m / 500ft.
  • Movement: Caliber 8900 Master Chronometer, twin barrels, 39 jewels, 25,200 vph, 60-hour power reserve.
  • Magnetic resistance: 15,000 gauss.
  • Sapphire front and caseback, screw-down crown.
  • Dial text: applied OMEGA logo, "SEAMASTER", "CO-AXIAL MASTER CHRONOMETER", "150m / 500ft".
  • Date at 6 o'clock inside a metal frame.

Genuine Diver 300M 41mm specs

  • Case: 41mm steel, 300m.
  • Helium escape valve at 10 o'clock.
  • Wave-pattern dial, skeleton hands.
  • Ceramic bezel insert from 2012 onward.
  • Dial text reads "300m / 1000ft".

What replica versions use

Replica Aqua Terra 41mm cases measure 40.5mm to 41.5mm with calipers. Movements fall into three groups: a Seagull ST2130, an A2824, or a decorated clone stamped 8900. All three have one barrel. The genuine 8900 has two. Power reserve on a replica lands at 38 to 42 hours, not 60.

Replica Diver 300M watches at 41mm copy the older case. Many use a Miyota 8215 or an A2824. The helium escape valve on most replicas is a sealed cosmetic part with no gas path.

Checks

  1. Measure the case and thickness. 41.0mm wide and 13.2mm thick on the Aqua Terra.
  2. Inspect the date window at 6. The frame sits flush with the dial on the genuine part.
  3. Run a finger over the teak lines. Genuine ridges are cut into the dial, not printed on it.
  4. Read the caseback. The reference number is 8 digits, etched at the case edge.
  5. Turn the crown. Genuine threads take 8 to 10 turns with no grit.
  6. Check lume under UV. Genuine Super-LumiNova reads blue on hands and markers.

Price bands

Genuine Aqua Terra 41mm on a steel bracelet lists near $5,700 to $6,200. The Diver 300M lists near $5,900. Replica prices sit between $120 and $500. A seller asking $1,000 for a "Swiss made" Aqua Terra is selling a replica at a markup.

Limits

No replica carries METAS certification. METAS runs eight tests on each movement, including 15,000-gauss exposure and a daily rate of 0 to +5 seconds. A replica has no water resistance test to 150m or 300m. Do not swim with one.