A recent spate of hooliganism in Poland has raised fears of violence from the country's fans, even if there were no reports of disturbances after their team's 2-0 loss to Ecuador last week.
Authorities say they are confident that Wednesday's tense encounter between hosts Germany and Poland - once geopolitical rivals, but now common members of the European Union - will remain peaceful.
The threat of hooliganism had been a theme security forces concentrated on ahead of the tournament, with this first round fixture, for obvious reasons, appearing one of the most dangerous.
A special train carrying 700-800 Polish fans left Warsaw early Wednesday morning and was scheduled to arrive in Dortmund in the late afternoon, Rafal Wasiak, the spokesman for Polish police working in Germany, told The Associated Press.
Three chartered planes and 70 chartered buses will also bring Polish fans to the match. Police estimate some 20,000 Polish fans will be in and around the stadium in Dortmund for the Poland-Germany match.