Firstly, the Google Authenticator application does not require a network connection. See: http://support.google.com/a/bin/answer.py?hl=en&answer=1...

If you are planning to be without your phone, you can always disable 2-step verification temporarily: https://support.google.com/accounts/bin/answer.py?hl=en&...

Finally, if you lose your phone, you should always have your single-use backup verification codes to allow you to login.

Ironical as it may be and as the author mentioned briefly in the article, "there is an app for that". Google provides an authentication app for at least Android and iOS.

I personally put my phone in "airplane mode" for the trip (still waiting for that market changing deal where you can travel easily across the globe and call/use data without being robbed by your provider) then use the authentication app. I also carry my authentication codes during the trip and they should be enough for even a longer trip, if not, I can generate new security codes during the trip using the security codes I already have with me.

Also iOS and blackberry:

http://support.google.com/accounts/bin/answer.py?hl=en&a...

And since they use a standard (RFC6238), there are third-party application that works with it too. I use a J2ME app on my Symbian phone.

What J2ME app are you using? I ended up porting (really just copying one Java class) part of Google Authenticator to J2ME. It works, but isn't great. What're you using?

(Sorry for the late reply)

I use an app from DS3: http://ds3global.com/index.php/en/news-a-events/news/97-secu...,

It's extremely simple, it just generates OTPs, nothing more.

When I'm travelling and expect to be using dodgy internet connections & cafes -- I set up a separate email account and forward my email to it. If that account gets hacked, I just turn off the forward.

That's exactly what I've been wondering about enabling two factor authentication for something I use as often as email.

Apparently you can print a series of one-time use verification codes that work any time to sign into your two-factor account. Stick a few on a card in your wallet and don't forget to generate more before you're out!

https://support.google.com/accounts/bin/answer.py?hl=en&...

When you do run out of verification codes, but you do have a working phone the 6 digit codes can also be sent to you through text messages or even a phone call from Gmail.

See http://news.ycombinator.com/item?id=3855880

Generally SMS are free to receive even while roaming (for countries where SMS are free to receive, i.e. places that aren't North America)

That's what the recovery codes are for. I keep them in my Dropbox. (This happened to me last year in Thailand, where I had zero cell reception.)