How can I report / block spam text messages on my AT&T iPhone?

To report a spam SMS message received on your iPhone, you can forward the text to the number SPAM (7726). AT&T will reply with a text asking for the phone number of the person who sent the spam text message.

Reply with the phone number and that's it. Text messages reported as spam and the replies from AT&T are not counted towards your data plan or monthly text allowance.

Blocking SMS spam from phone numbers requires signing up for AT&T Smart Limits for Wireless which costs $4.99 per month. If the text message came from another source, such as an email address or SMS short code you have these options:

For spam sent from an SMS short code:
Reply to the spam text message with the word STOP in the body of the reply.

To block a specific email address:
Sign in to your AT&T Mobility account and create a Message Preferences account. Add email addresses to the block list by replying to the spam text with BLOCK in the reply message.

To block all emails addressed to your default iPhone SMS email:
Normally texts can be sent to the email address assigned to your iPhone, which is an email address starting with your 10-digit wireless phone number @txt.att.net. Changing this email alias will prevent spammers from randomly sending to your SMS email.

To do this, log into your AT&T account and create an email alias for your iPhone in Messaging Preferences. Then change the Mobile Number Control settings so that only text messages addressed to your new email alias will be delivered.