Go without a SIM card

[samnpam]

When going to exotic vacations, you don't want annoying calls / SMS & pay for them.

So, take out your SIM card, and use your phone the smart way — as an alarm clock or a Wi-Fi browser, whatsapp or skype credits to call back.

***Edited to add Labels***

[nick67]

You can also simply put your phone into Airplane Model which will turn off all cellular connections.