Pre-owned Omega Seamaster Planet Ocean 600M ref. 217.30.42.21.01.003 (2026). The Planet Ocean has served as Omega’s flagship professional dive watch since its debut back in 2005. In many ways, it is a more robust alternative to the Seamaster Diver 300M while delivering the brand’s latest advancements in movement technology and case construction. Twenty years later, Omega ushered the collection into its fourth generation with the ref. 217.30.42.21.01.003, delivering the most comprehensive redesign in the model’s history. While earlier Planet Oceans shared visual DNA with other Seamaster models, this one carves out an identity of its own. The case has been completely reworked with sharper lines and a more angular profile, while the familiar lyre lugs and helium escape valve have been retired in favor of a cleaner, more streamlined design. Beneath the crystal, Omega incorporated technology derived from the Ultra Deep collection, including an internal titanium reinforcement ring that strengthens the case without altering the watch’s overall appearance. The dial is still very much a Planet Ocean dial, featuring bold arrow hands, oversized hour markers, and Arabic numerals at the cardinal positions for exceptional legibility. A redesigned ceramic bezel with deeper knurling and a simplified diving scale completes the modernized aesthetic. Shop OMEGA Seamaster Collection