As we know, the messages app in the iPhone will detect if the party you are texting to is iMessage compatible or not, and will then send an iMessage instead of an SMS. This is great, and works as advertised with other iPhone users that have data plans.

However, what happens with an iPhone with NO data plan? (bought it unlocked, for example). The ideal situation for me, would be that the message is first tried to be delivered as an iMessage, and after some time it would time out and be delivered as an SMS instead, but I don't think that's the case.

Does anyone has experience with this? Will iMessage fall back to SMS on a per message basis?

3 Answers 3


Yes, it will.

I've experienced it a few times, if the message stays undelivered for something between one to five minutes (I haven't checked exactly), it will fallback to SMS.

This behavior can be changed in Settings > Messages > Send As SMS, checking it off will not send the message as SMS if iMessage is not available. Rechecking it will send the message not delivered (even if they were sent before).

  • Actually - I've been playing with this feature (disabling the Send as SMS toggle) on iOS and it's not reliably stopping messages. It seems to send whether I want it to or not when I address a message to a phone number. Perhaps it's more nuanced and only works for contacts that have both SMS and iMessage and are perfectly linked. I'll post an honest answer if I can resolve exactly what is broken in my understanding of how this should or does work.
    – bmike
    Commented Jan 31, 2012 at 16:39

A couple of answers I have found since I am in the USA for a vaction from Canada and HAve the Data Roaming turned off, I have a friend with a 4S Phone and if I am using wifi I can send an iMessage but if I am not on wifi it will not deliver the message till after I go back on Wifi.

I have found two possible answers that will send those messages by SMS instead

Option One.... Using Siri say "Siri, send Mary Jones a text" Doing this will send a SMS rather than an iMessage

Option Two... If writing a message in iMessage when done press "Send" then Tap and hold the message itself this will give you the option of sneding it as a SMS Message.

Hope that helps people, I think it works for me, will test it later tonight.


My experience of this is less friendly. iMessage is chosen automatically for recipients with iOS devices. But it often fails (no clear reason why). When it does so, it throws a "message not delivered" error. At this point I can choose to send via SMS, but it doesn't happen automatically (over several hours).

This is typically when I'm connected via 3G on Vodafone in the UK. I have "Send as SMS" turned on.

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