Going to Germany for 13 days. Is there anything I need to know/do with my AT&T iPhone beforehand?

This is my first time out of the country. I'm okay with just using Wi-Fi for iMessaging and social media posting while abroad from the United States. Is there a way to reject all calls and SMS messages so I won't be charged? Also, is it worth it to get a temporary international plan?

Just make sure you turn off data once you leave the country. Should be an option for that in the settings somewhere.

If you want to get a plan, I would suggest Vodafone… They have a prepaid plan that includes some texts and data for around 10 euros. Just pop into a Vodafone shop and use your hotel's address as the billing address, and ask them to change the SIM card for you.

Before you leave the US, turn on Airplane Mode and then turn Wi-Fi on. His way your cellular data and phone features will be turned off.

If your phone is paid for and you are out of contract, you can have AT&T unlock your phone, so you can use a SIM card from a carrier while in Germany, you will be able to make local calls while in Germany, and depending on the type of prepaid plan you get, you may also have data to use while out and about and not have to plan Wi-Fi usage.