The Sixt office is right in the Bahnhof. However, their hours are limited and sometimes they're not open as long as they post. The parking garage is a bit of a walk from the Sixt office. Cross the street, walk through an outdoor shopping mall and into the garage. There's a garage much closer - right at the Bahnhof, but Sixt uses the 7th floor of another garage. Returning the car was tricky because the GPS kept taking us to the closer garage and we just couldn't find the entrance to the Sixt garage, so we actually had to leave the car in the garage that we could get into then walk the keys to the Sixt garage and send them an email explaining. I was so worried! But the Sixt agents were very kind and understanding. All turned out fine. The car was comfortable and seemed brand new. We drove it to Niederstotzingen (about a 20min drive) and back. There was no USB charger for phones- they had a smaller, oval-shaped charger and a charging pad though. I would definitely use Sixt at Ulm Bahnhof again and am so grateful for the Sixt employees who helped and were understanding about the parking situation.