Taxis are available around the clock at both terminals and the long-distance train station.
When arriving at Frankfurt Airport, tell the taxi driver the name of your airline. You'll then be taken to the right terminal and dropped off at the curb as close as possible to your check-in counter.
The trip from Frankfurt city center to the airport (and vice versa) takes between 20 and 30 minutes, depending on traffic.
Large-capacity taxis for up to seven persons are also available in the Frankfurt area.