The Ocean Star is one of the oldest and most successful models in the Mido catalog. The first Ocean Star debuted in 1944, making it one of the earliest water-resistant watches. Its single-shell (or "monocoque") stainless steel case and then-revolutionary cork sealing system made waves in the industry.

Today, the Ocean Star has grown into a comprehensive collection of modern diving watches. Each timepiece has a unidirectional diving bezel, luminous hands and indices, sapphire crystal, and a screw-down crown. While most models are water-resistant to 200 m (20 bar, 656 ft), top models can dive down to 600 m (60 bar, 1,969 ft).

Mido outfits most Ocean Star watches with an automatic caliber from ETA, a Swiss movement manufacturer. The caliber 80 with an 80-hour power reserve powers the majority of the current collection. Some models even come with a chronometer certificate from COSC (the Official Swiss Chronometer Testing Institute). The Ocean Star collection has also contained quartz-powered watches since the 1970s, including the Captain Quartz Chronograph.