Lucien Favre's side arrived in the English capital later than originally planned on Tuesday after their 18-year-old winger and defender Abdou Diallo arrived at the airport without the important document.
Both players returned their respective homes to collect their passports, before being able to complete the rest of the journey, according to BBC Sport.
German daily newspaper Rehr Nachrichten posted footage to their Twitter page of Sancho being let through security at Dortmund Aiport to join the rest of the team.
— Florian Groeger (@RN_Florian) February 12, 2019
The club confirmed that Sancho had made the trip in a post on Twitter, calming any fears he would have to travel alone or miss the game entirely.
— Borussia Dortmund (@BVB) February 12, 2019
Sancho is expected to start against Spurs, having scored eight goals and contributed 11 assists in all competitions this season for the Bundesliga leaders.
Frenchman Diallo is also expected to begin the game at centre-back having started five of Dortmund's six group games.