Question: In German, the word *Fernweh* translates roughly as "farsickness." It denotes the desire to be somewhere other than where you are now. It was coined as an antonym to *Heimweh*, or "homesickness."

Does English have a good word to indicate the feeling of wanting to be somewhere else?

Answer: 
Depending on the context, *wanderlust* might work for you:
["strong longing for or impulse toward wandering" (M-W)](http://www.merriam-webster.com/dictionary/wanderlust), depending on how much you associate Fernweh with the act of travelling as opposed to the state of being away from home.
Sometimes I use the phrase "**a travel itch**" when I stay home too long.

It might be described as 

* "the feeling someone gets when they've stayed home for too long, knowing there is a lot to do and see elsewhere.