Wi-Fi Apps

I will be visiting Tokyo for 7 days with my daughter and I want to be able to call home (US). I am signing up with ATT International for texting, phone calls and data. Will I be able to connect with Tokyo's wifi through ATT or do I need to download an app for free wifi in Japan? If I need to download an app, do I need more than one? Why do Japan have so many wifi apps?

Will I be able to connect with Tokyo's wifi through ATT or do I need to download an app for free wifi in Japan?

You can connect directly when free networks are available, but there are 2 apps that will streamline the process so you don't have to sign in all the time:

http://www.ntt-bp.net/jcfw/en.html
http://wi2.co.jp/tjw/english.html

More info on internet in Japan:

http://www.japan-guide.com/e/e2279.html

Thank you for the information. I will download both apps to my IPhone 5s. Because I will have to register to use the apps, should I do this in Tokyo or US? We will be leaving for Tokyo on the 15th of July.

It's ok to register in Japan. And I don't think its even possible unless the network is available.