The Seiko Prospex Sumo SPB103J—proudly Made in Japan—is a bold and iconic diver’s watch beloved by Seiko fans around the world. Nicknamed the “Sumo” for its powerful case shape, broad stance, and distinctive 12 o’clock marker, this model embodies strength, durability, and unmistakable Seiko character.

The vibrant green dial of the Seiko SPB103J is paired with large LumiBrite hands and markers for exceptional underwater visibility, while the robust stainless‑steel case and bracelet deliver reliability in demanding conditions.

Powered by Seiko’s high‑performance 6R35 automatic movement, the SPB103J offers an impressive 70‑hour power reserve and the precision engineering Seiko is renowned for. With a sapphire crystal, screw‑down crown, unidirectional rotating bezel, and 200m water resistance, this Prospex diver carries forward Seiko’s heritage of pioneering dive‑watch craftsmanship since the debut of Japan’s first diver’s watch in 1965.

What we love about the Seiko Sumo SPB103J. The SPB103J captures everything that makes the Sumo a fan favourite—rugged presence, exceptional build quality, and brilliant legibility. The green dial adds a modern twist to a true Seiko classic, while the 6R35 movement provides dependable, long‑lasting performance. It’s a standout diver that blends heritage, precision, and everyday wearability in one unmistakable design.

Orders are dispatched within 1–3 business days from Sydney via Australia Post Express for fast and reliable delivery. Customers located in Sydney may also enjoy the convenience of same‑day Click & Collect, with orders ready for pickup from our Alexandria showroom just one hour after purchase when this option is selected at checkout.

Every watch is covered by a 3‑year Seiko Australia warranty, providing complete peace of mind. StarBuy is an Authorised Seiko Distributor, and all watches are supplied in genuine Seiko original packaging. Warranties are registered online directly with Seiko, and following dispatch, Seiko will email you confirmation of your warranty registration along with a link to the online instruction manual. In line with Seiko’s current sustainability practices, printed warranty booklets and manuals are no longer supplied.