Grand Seiko Sport GMT SBGN003

The case measures 39mm across and 12.1mm thick, with a 19mm lug width. Case material: Stainless steel. Case size alone is a poor guide to how a watch wears; lug-to-lug length and how the bracelet drops off the case matter more, which is why we suggest trying one on before you commit.

High-accuracy quartz GMT, Cal. 9F86 (+/-10 sec/year).

It is rated to 100 meters, about 328 feet. That is enough for swimming and snorkeling, but not for scuba diving. One caution that applies to every watch on this page: a water resistance figure describes a new watch with fresh gaskets. On a piece that is years past its last service, treat the rating as unknown until it has been pressure tested.

Grand Seiko produced this reference from 2019 to the present day. Production years matter when you are valuing one, because dial, bezel and bracelet details often changed inside a single reference run.

SBGN = 9F quartz GMT; 003 = steel black-dial Sport GMT. Reading the reference is the fastest way to confirm that a watch is what the seller says it is, before you get anywhere near the movement.

Quartz GMT Sport. Collector nicknames are not official Grand Seiko names, but they are what people actually search for and what they are called across a showroom.

Yes. We buy this reference outright, and we lend against it if you would rather keep it. We are a family-owned San Diego buyer established in 2006, our appraisers are GIA-trained, and the appraisal is complimentary with no obligation to sell. You can bring it to our Gaslamp showroom at 907 Sixth Ave or start online. If you are looking to buy this reference instead, tell us and we will let you know when one comes in.