Will WhatsApp deliver a message that was accidentally sent while data was off? I'm using Whatspp on a Moto G (1st Gen) mobile. Today I've accidentally sent a message to my friend while my mobile data was in off mode. I have deleted that message immediately. Now will the message be delivered to my friend if i turn on the mobile data?
Assuming that you didn't have any access to internet at that time (No WiFi and mobile data was turned off) and deleted the message (by tapping and holding the message, then choosing "Delete"), it's very likely that the message was not sent.

This is a result by self-testing:


Send message while not connected to internet, then try to connect to internet: Message sent
Send message while not connected to internet, delete the message, then connect to internet: Message is not sent


Lastly, the best way to ensure it is to ask the recipient.