The Omega Seamaster Diver 300M originally premiered in 1993 as a chronograph. A three-hand version followed relatively soon thereafter. Just like its famous sister, the Seamaster 300, the Diver 300M is also water resistant to 300 m (30 bar, 984 ft). However, a helium escape valve at 10 o'clock helps to set the Diver 300M apart. This feature is especially important for saturation diving, where divers breathe a mix of oxygen and helium. Helium can enter the watch and cause damage during the decompression process if it's not released.

Another distinctive detail is the date display included on every Diver 300M. Its design is also much more modern. The bezel's wavy edge, in particular, gives this timepiece a special appearance. Omega offers this watch in sizes ranging from 28 to 42 mm. Most models are made of stainless steel, though some limited editions also come in titanium or extremely rare tantalum.

In the beginning, this professional diving watch was available with a quartz or automatic movement. Omega only uses mechanical movements for the current collection. These movements are not only chronometer-certified but also have been outfitted with Omega's Co-Axial escapement since 2006. At Baselworld 2018, the Biel-based manufacturer announced a new edition that will include their in-house Master Chronometer caliber, which can resist magnetic fields of up to 15,000 Gauss.