The man, named by Kent Police as 40-year-old Abdul Rahman Haroun, appeared in court in Kent on Thursday to face charges of "causing an obstruction to an engine or carriage using the railway."
He remains in custody and is due back in court on August 24.
His alleged attempt to walk to Britain comes against the backdrop of thousands of attempts
in recent days by migrants camped near the tunnel's entrance in Calais, northern France, to breach security and find a way to reach the United Kingdom.
These breaches have seriously disrupted traffic and resulted in at least one death.
Most migrants try to sneak onto vehicles before they are driven onto the trains that carry them through the tunnel to Folkestone, in southeastern England. But Rahman Haroun is accused of trying to do it on foot -- and, unusually, having almost made it.
"During the night of Monday to Tuesday, a Sudanese migrant almost succeeded walking through the tunnel," Eurotunnel spokesman Romain Dufour told CNN.
Kent Police said the man was located near to the tunnel's Folkestone terminal a little after 6 p.m. on Tuesday.
Eurotunnel posted updates to its Twitter account Tuesday warning of delays of up to four hours for travelers heading from Folkestone to Calais as a result of an "unplanned tunnel inspection."
The tunnel allows trains carrying passengers and freight to whiz beneath the English Channel in either direction at more than 80 miles per hour, in a journey that takes about 35 minutes.
There are in fact three tunnels -- a single-track rail tunnel running in each direction and a service tunnel between.
Calais has long been a gathering place for migrants trying to find a way into the United Kingdom. This year alone, Eurotunnel has intercepted some 37,000 migrants, the operator said.
French and UK authorities have been taking steps to boost security around the tunnel's Calais entrance in light of the recent mass incursion attempts, which have disrupted services on what is a key trade and tourism link between Britain and the rest of Europe.
Dufour, the Eurotunnel spokesman, said, "Positive support from the two governments over the past two weeks has brought order to the local area and confined the disruptive actions of both migrants and protesters.
"Additional Border Force resources to process trucks more quickly and efficiently; enhanced security fencing; additional security guards; extra cameras, infrared detectors, patrols and sophisticated new security measures provided recently have seen traffic disruption significantly reduced and illegal entry into the UK brought back under control."
Full freight services are now running again, he said, following temporary suspensions during the peak of the disruption.