The group, which moved into Germany's lucrative rail market in December, grew turnover across all its divisions during the first quarter, with underlying passenger growth of 3%.
National Express has been given a boost by fresh inroads into the international market, including the rail service deal in Germany and a bus contract in Bahrain.
In its latest update, the group said it was eyeing other "emerging opportunities."
Dean Finch, group chief executive of National Express, said: "Our new businesses in Germany and Bahrain are already carrying millions of passengers."
He added: "It is these successes that convince us that our strategy of diversification into new markets in a measured way, when the conditions are right, remains the right one."
The group said the German rail operations had carried more than six million passengers since the start of 2016, while it has notched up over a million passengers every month on its Bahrain bus services.