The event has been held every October since 2011, drawing over 5,000 competitors across the three days of races.
The mini Marathon is open to all, regardless of amateur status, so long as participants are at least 18 years old and able to pay the registration fee.
The island and its residents play a major role in the Spetses mini Marathon.
The event is organized by Athens-based Communication Lab, with support from the municipality of Spetses, the Greek National Tourism Organisation (GNTO), and hundreds of local volunteers.
The 3 and 5 km swimming routes cross (once and twice, respectively) the strait separating Spetses from the town of Kosta on the mainland, while the 1.5 km swim starts in front of the Poseidonion Grand Hotel.