Several rulers in antiquity dreamt of cutting a canal through the Isthmus. The first to propose such an undertaking was the tyrant Periander in the 7th century BC. He abandoned the project due to technical difficulties, and instead constructed a simpler and less costly overland portage road, named Diolkos. According to another theory, Periander feared that a canal would have robbed Corinth of its dominating role as entrepôt for goods. Remnants of the Diolkos still exist next to the modern canal.
The Diadoch Demetrius (336–283 BC) planned to construct a canal as a means to improve his communication lines, but dropped the plan after his surveyors, miscalculating the levels of the adjacent seas, feared heavy floods.
The historian Suetonius tells us that the Roman dictator Julius Caesar (r. 48 to 44 BC) projected, among other grandiose engineering schemes, a canal through the Isthmus. However, he was assassinated before he could bring the scheme to fruition.
The Roman Emperor Nero (r. 54–68 A.D.) actually launched an excavation, personally breaking the ground with a pickaxe and removing the first basket-load of soil, but the project was abandoned when he died shortly afterwards. The Roman workforce, consisting of 6000 Jewish prisoners of war, started digging 40–50 m wide trenches from both sides, while a third group at the ridge drilled deep shafts for probing the quality of the rock (which were reused in 1881 for the same purpose). As the modern canal follows the same course as Nero's, no remains have survived.
The modern attempt at construction began in the 1870's following the successful opening of the Suez Canal. A French company was hired to build it, but due to financial difficulties, the company ceased work after only the two ends had been dug. Finally, in 1881 the Hungarian architects István Türr and Béla Gerster, who had also been involved with early surveys for the Panama Canal, were hired to plan a new canal. A Greek company led by Andreas Syngros (the main contractor being Antonis Matsas) ultimately took over the project and completed it in 1893.
At each end of the canal, seashore roads cross using submersible bridges that are lowered to the canal bottom to allow maritime traffic to pass.