After years of constant delays that has seen the project become a standing joke among Turks, Erdogan on Friday evening is due to glide into Istanbul aboard the first train.
The opening comes ahead of presidential elections on August 10 that are expected to see Erdogan sweep to victory as head of state, after a campaign in which he has constantly boasted of his efforts to improve transportation in Turkey.
But the project has been hit by repeated postponements of the opening date and mishaps -- including when one of the new trains crashed into a maintenance vehicle this month.
The line will not terminate in the centre of Istanbul, but on the Asian side of the Bosphorus in the suburb of Pendik, some two hours from the centre in the city's often heavy traffic.
There are safety concerns too: train accidents are frequent on Turkey's network and in 2004 dozens of people were killed when a newly-inaugurated high-speed train derailed in the northwest.
Yet, with an intense if belated advertising campaign -- TV adverts show smiling children waving at the train as it surges through the fields -- the government is now pulling out all the stops to make it a success.