Omega · Omega 8900

Omega Aqua Terra 41, Planet Ocean 43.5 and Globemaster power reserve: inside the calibre 8900

The Omega Seamaster Aqua Terra 41, Planet Ocean 600M 43.5, Globemaster, Constellation 41 and De Ville Hour Vision run on the calibre 8900. From full it runs about 60 hours, two and a half days.

Updated September 2026 · Based on manufacturer specs, published reviews and watchmaker/owner reports

Watches that use the Omega 8900

The 8900 is Omega's full-size, two-barrel Master Chronometer movement and the base of most of its automatic range above 40 mm. It was Omega's first METAS-certified movement, and it has since spawned a family: the 8912 without a date, the 8906 GMT and the 8938 and 8939 worldtimers share its architecture and its 60-hour reserve.

Close relatives worth knowing: the Seamaster Planet Ocean Ultra Deep and the newest Planet Ocean use the 8912, a no-date version. The Planet Ocean GMT uses the 8906, and the Aqua Terra Worldtimer uses the 8938 or 8939. All run about 60 hours.

Specs at a glance

History and where it came from

Omega's first in-house base movement of the modern era was the 8500, launched in 2007 in the De Ville Hour Vision. It had two barrels for 60 hours, a co-axial escapement, and an hour hand that could be set on its own in one-hour steps. Silicon hairsprings arrived soon after, and in 2013 Omega showed it could make movements that shrug off 15,000 gauss.

In 2015 Omega and the Swiss Federal Institute of Metrology (METAS) introduced the Master Chronometer standard, and the 8900 in the new Globemaster was the first movement to meet it. Every watch is tested as a cased watch for accuracy at 0/+5 seconds a day, for power reserve, for water resistance and for function in a 15,000-gauss field. The certificate comes with an online record of the results for that watch.

The 8900 then spread across the catalogue: the Planet Ocean in 2016, the redesigned Aqua Terra 41 in 2017 (when the date moved from 3 to 6 o'clock) and the Constellation in 2020. Monochrome noted in 2017 that Omega was fitting Master Chronometer movements to every model except the hand-wound Speedmaster Moonwatch, which caught up in 2021 with the 3861.

Accuracy in the real world

The 0/+5 seconds a day figure is measured on the finished watch, in several positions and temperatures, and again after magnetic exposure. That's stricter than the COSC -4/+6 test of an uncased movement, and it's why an Aqua Terra or Planet Ocean often runs better than its price class would suggest.

Owners on watch forums generally report daily rates inside the spec. The two barrels help here: the mainspring's torque stays steadier for longer, so the rate holds up better as the watch runs down over a weekend. The silicon hairspring means a laptop, handbag clasp or speaker won't magnetise it into gaining minutes a day, which is still one of the most common faults in ordinary automatics.

Reliability and servicing

The 8500 and 8900 family has been in production for well over a decade without a well-known systemic problem. Omega's current product pages list a five-year warranty on 8900 watches.

• Brand service. Omega is the realistic route. The co-axial escapement, silicon parts and Master Chronometer testing sit within the Swatch Group network.
• Independents. Omega-approved watchmakers can service it; general independents usually can't get parts.
• Thickness. Two barrels and a big rotor make it a tall movement. It's part of why the Planet Ocean 43.5 and Aqua Terra 41 are thicker than some rivals, at 13.2 mm for the Aqua Terra 41.

Quirks worth knowing

• Jumping hour hand. In the first crown position you can move the hour hand in one-hour jumps without stopping the watch. It's handy for travel and daylight saving time. The date follows the hour hand forwards and backwards past midnight.
• No separate date quickset. Because the hour hand drives the date, you set the date by jumping the hour hand through midnight. It takes a while at the start of a month.
• The date. As with most date movements, take care with any setting late at night. Here's why.
• Size. At 29 mm it doesn't fit in smaller cases. That's why the Aqua Terra 38 and Planet Ocean 39.5 use the 55-hour 8800.

How it compares

• Omega 8800: the compact single-barrel sibling in the Diver 300M and Aqua Terra 38. It has 55 hours and no jumping hour hand.
• Rolex 3235: the Datejust 41 and Submariner Date movement, the obvious Aqua Terra rival. It has 70 hours and a -2/+2 s/day rating; the Omega has better magnetic resistance.
• Rolex 3285: the GMT-Master II's jumping-hour movement, which works much like the 8900's hour hand, with 70 hours.
• IWC 82000: another 60-hour in-house automatic, from the Portugieser and Ingenieur.
• Omega 9900: the chronograph built on the same two-barrel, 60-hour idea.

Living with the 60-hour reserve

Sixty hours is the point where a watch starts to survive the weekend. Take your Aqua Terra 41 off at 7pm on Friday with a full spring and it runs until about 7am on Monday. That's just enough if you're back at the watch box early. Leave it off from Friday afternoon, or after a week of desk days that left it half-wound, and it will have stopped by Monday.

So on a Planet Ocean or Aqua Terra, whether it survives a weekend depends on how full it was on Friday, not just on the 60-hour figure. Watch Winder counts down the reserve for each watch you own and reminds you before one stops, so a short Sunday wear or a few turns of the crown keeps it running. For a specific weekend or trip, try the "Will my watch stop?" calculator.

Verdict

The 8900 is one of the best all-round automatic movements in its price range: certified 0/+5 s/day on the finished watch, 15,000-gauss magnetic resistance, a traveller's jumping hour hand and a 60-hour reserve that nearly covers a weekend. The costs are thickness, and servicing that goes through Omega rather than any watchmaker. If you want an Aqua Terra or Planet Ocean for daily wear with the odd weekend off, it's hard to fault.

FAQ

How long does an Omega Aqua Terra 41 run off the wrist?

The Aqua Terra 41 with the calibre 8900 runs for about 60 hours from a full wind, two and a half days. If it was only partly wound, it stops sooner.

What is the power reserve of the Omega Planet Ocean 43.5?

About 60 hours. The Planet Ocean 600M 43.5 uses the two-barrel calibre 8900, while the smaller 39.5 mm model uses the 8800 with 55 hours.

Does the Omega Aqua Terra hack?

Yes. Pulling the crown to the time-setting position stops the seconds hand, and you can wind the 8900 by hand through the crown.

How accurate is the Omega Aqua Terra 41?

It's a METAS-certified Master Chronometer, tested as a complete watch to run between 0 and +5 seconds a day. It's also certified to resist magnetic fields of 15,000 gauss.

How do I change the date on an Omega Globemaster or Aqua Terra?

Pull the crown to the first position and move the hour hand in one-hour jumps. The date changes each time the hour hand passes midnight, forwards or backwards.

Will my Omega Planet Ocean survive the weekend in a drawer?

Only if it was fully wound. Sixty hours from Friday evening lasts to about Monday morning, and a partly wound watch will stop on Sunday.

What is the difference between the Omega 8800 and 8900?

The 8900 is larger, with two barrels for 60 hours and a jumping hour hand. The 8800 is smaller, with one barrel for 55 hours, and fits 38 to 42 mm watches such as the Diver 300M.

Sources

• Omega: Seamaster Aqua Terra 150M 41mm 220.10.41.21.03.001
• Monochrome: Omega Globemaster review, fully explained
• Monochrome: 2017 Omega Seamaster Aqua Terra Master Chronometer 41mm
• Monochrome: History of the Omega Seamaster Planet Ocean, 2005 to 2025
• WatchBase: Omega caliber 8900

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 15 hours of wear fills the Omega 8900. Desk days charge more slowly.
• Most automatics can also be wound by the crown. If yours has stopped, a few dozen turns gets it going before you put it on.
• Off the wrist it stops about 60 hours after it was last full. Stopped sooner?
• On a watch winder, start at about 650 turns per day, both directions. Winder settings for every movement.
• If it does stop, don't set the date between 9pm and 3am. Check if it's safe.

All Omega movements

Never let it stop

Watch Winder counts down the reserve of every watch you own and reminds you before one stops. It already knows the Omega 8900: type your watch's name and the reserve fills itself in.

Manufacturer's published figure. Real reserve varies with the watch's age and service; check your manual.