Wiesbaden is very well connected by many highways from Frankfurt, Cologne or Mainz. Trains travel frequently and are very enjoyable. Travel times by car are roughly 15 minutes from Mainz, 30 minutes from Frankfurt, or 2 hours from Cologne / Köln.
From The Airport
A taxi from Frankfurt Airport FRA to Wiesbaden costs around €60. Unless it's the middle of the night and you've missed the last train public transport S-Bahn or Deutsche Bahn is a much better deal at €3.80 one-way.
From the Terminal 1, follow the signs to the regional train stationFrankfurt(MainFlughafen Regionalbahnhof) which is in the basement of the Airport building. Usually Wiesbaden is the terminal station for the S-Bahn/regional train so you can easily find the correct platform. Note: There are two train stations at the airport; in the basement the regional train station S-Bahn & fast regional trains and one for mid-/long-distance Fernbahnhof trains.
The long-distance train station is a longer walk about an extra 7-12 minutes and has much less frequent service to Wiesbaden.
Please see additional notes in the sections below regarding train tickets.
By car
If you start in Frankfurt, take the A66 until Wiesbaden-Erbenheim Exit 6. Here you follow the signs to Wiesbaden City Center and Wiesbaden Kurhaus.
If starting from the Frankfurt Airport follow signs for Wiesbaden, which takes you on the A3 until the Wiesbadener Kreuz, where you switch to the A66 until Exit 6.