Omega · Omega 8800

Omega Seamaster Diver 300M, Aqua Terra 38 and Planet Ocean 39.5 power reserve: inside the calibre 8800

The 42 mm Omega Seamaster Diver 300M, the 38 mm and 34 mm Aqua Terra, the 39.5 mm Planet Ocean and the Railmaster all run on the calibre 8800 or a close variant. From full it runs about 55 hours, or two and a quarter days.

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

Watches that use the Omega 8800

The 8800 is Omega's compact, single-barrel Master Chronometer movement. It goes wherever the larger two-barrel 8900 won't fit or isn't needed, which includes the most famous Omega after the Moonwatch: the "Bond" Seamaster Diver 300M. Variants with different numbers change the display, not the basics. The 8806 is the no-date version and the 8804 has small seconds.

Specs at a glance

History and where it came from

For about two decades the Seamaster 300M ran on Omega's calibre 2500, a co-axial movement built on the ETA 2892 architecture. When Omega made its own base movements, the 8500 family in 2007, they were big: 29 mm across with two barrels. That suited 41 to 45 mm watches, but not a 38 mm dress-sports watch.

In 2015 Omega introduced the 8900 and its METAS "Master Chronometer" standard. The 8800 followed as the compact, single-barrel version, arriving around 2016 in the 39.5 mm Planet Ocean and then spreading through the Aqua Terra 38, special Seamasters and the 2017 Railmaster. Its biggest moment came at Baselworld 2018, when Omega rebuilt the Seamaster Diver 300M for its 25th anniversary. The case grew from 41 to 42 mm, the wave dial came back, the date moved to 6 o'clock, and the 8800 replaced the 2500 behind the Diver's first sapphire caseback.

Monochrome summed up the change: compared to the ETA-based 2500 the new calibre was "a massive upgrade". It was antimagnetic, precise and had a comfortable reserve.

Accuracy in the real world

Every 8800 watch is tested by METAS as a complete watch, and the headline figure is 0 to +5 seconds a day. That's tighter than the COSC -4/+6 standard and is measured on the cased watch, including after exposure to 15,000 gauss.

Owners on watch forums generally report Seamaster 300Ms and Aqua Terras running within that window. As with any mechanical watch, how you wear it matters: a watch left dial-up overnight can run at a different rate from one left crown-down. The silicon hairspring is the real-life advantage. A magnetised hairspring is one of the most common reasons a watch suddenly starts gaining minutes a day, and the 8800 is effectively immune to the fields you meet in daily life.

Reliability and servicing

The 8800 has been in wide production since 2016 without a known systemic fault. The silicon hairspring and co-axial escapement are designed to reduce wear, and Omega's current product pages list a five-year warranty.

• Brand service. Omega services it in-house and through its network. That's the realistic route, because co-axial parts and the equipment to test Master Chronometer performance sit within the Swatch Group.
• Independents. Some Omega-approved independents can work on it; general independents often can't get parts. That's a real difference from the ETA-based 300Ms of the 1990s.
• What wears. Screw-down crown seals and gaskets on the Diver 300M need regular checks if you swim in it, whatever the movement's service interval.

Quirks worth knowing

• No jumping hour. The 8900 lets you jump the hour hand for a new time zone without stopping the watch. The 8800 doesn't. You set the time in the usual way and the date has its own quickset.
• Number soup. 8800, 8801, 8802, 8803, 8806 and 8807 are the same family with different finishes, gold rotors or no date. The 8806 in the no-date Diver 300M and Railmaster has the same 55 hours.
• The date. On date versions, avoid setting it late at night. Here's why.
• Rotor noise. A bidirectional rotor can be heard spinning in a quiet room. It's normal.

How it compares

• Omega 8900: the bigger sibling, with two barrels, 60 hours and a jumping hour hand, in the Aqua Terra 41 and Planet Ocean 43.5.
• Rolex 3235: the Submariner Date movement, with 70 hours and a -2/+2 s/day Superlative Chronometer rating. It has a longer reserve and a tighter spec, and the Omega has more magnetic resistance.
• Tudor MT5602: the Black Bay movement, with 70 hours and COSC certification. It has more reserve for less money, but COSC rather than METAS.
• ETA 2892-A2: the base of the old calibre 1120 Seamaster 300M, with 42 hours. Far easier for any watchmaker, much weaker on magnetism and reserve.

Living with the 55-hour reserve

Fifty-five hours sits between the classic two-day movements and the 70-hour Rolex and Tudor calibres. In practice: take your Seamaster Diver 300M off at 6pm on Friday with a full spring and it's still running at 1am on Monday morning, so it will have stopped before you get dressed. If you went into the weekend having worn it only on a few desk days, it'll stop sooner.

That's why the Aqua Terra or Seamaster is easy as a daily watch and fussier as part of a rotation. A weekend on a different watch is enough to stop it. Watch Winder counts down the reserve for each watch you own and reminds you before one stops, so you can wear the Seamaster for an hour on Sunday afternoon or give it a few turns of the crown. To check a specific weekend, try the "Will my watch stop?" calculator.

Verdict

The 8800 is one of the reasons the modern Seamaster Diver 300M and Aqua Terra 38 are such strong buys. You get a certified 0/+5 s/day rate on the finished watch, practical immunity to magnetism, a nicely finished movement behind a display back and a reserve that comfortably covers a day off the wrist. The trade-offs are a reserve that falls short of a full weekend, and servicing that has to go through Omega or an approved watchmaker. If you want the weekend covered in an Omega, look at the 8900 models.

FAQ

How long does an Omega Seamaster Diver 300M run off the wrist?

The current Seamaster Diver 300M with the calibre 8800 runs for about 55 hours from a full wind, a little over two days. If it wasn't fully wound when you took it off, it will stop sooner.

Does the Omega Seamaster 300M hack?

Yes. The 8800 stops the seconds hand when you pull the crown out to set the time, and it can be wound by hand.

How accurate is the Omega Seamaster Diver 300M?

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

What is the power reserve of the Omega Aqua Terra 38mm?

The Aqua Terra 38 uses the calibre 8800, with about 55 hours of power reserve. The Aqua Terra 41 uses the 8900 and runs about 60 hours.

Why did my Omega Seamaster stop over the weekend?

Fifty-five hours doesn't cover a full weekend from Friday evening to Monday morning. It will stop even sooner if light wear left the spring only partly wound.

Is the Seamaster 300M No Date the same movement?

It uses the 8806, which is the 8800 without a date. It has the same 55-hour reserve and Master Chronometer rating.

Should I wind my Omega Seamaster by hand?

If it has stopped, yes. Wind the crown a few dozen turns before you put it on, so it doesn't depend on your wrist to get going. There's no need to do it daily if you wear it.

Sources

• Omega: Seamaster Diver 300M 210.30.42.20.03.001
• Monochrome: Omega Seamaster Diver 300M Master Chronometer hands-on (2018)
• Monochrome: Seamaster Aqua Terra 150M 38mm green dial
• Monochrome: Seamaster Diver 300M No Date, calibre 8806
• WatchBase: Omega caliber 8800

Keeping it running

• On an average day an automatic gains roughly 4 hours of reserve per hour on the wrist, so about 14 hours of wear fills the Omega 8800. 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 55 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 8800: 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.