With the Messages app on your iPhone, you can send and receive SMS/MMS text messages and also iMessages. When an iMessage is sent, it is routed through Apple’s servers when you are connected to the internet via your mobile data or WiFi. If you are not connected to the internet, the Messages app may try to deliver the iMessage as a regular SMS text message. This could involve texting charges for you, depending on the plan that you have with your mobile carrier.
How to deliver an iMessage as a regular SMS text message
It is possible to adjust the settings on the Messages app to establish if it will automatically send an iMessage as an SMS text message, if you don’t have a connection to the internet. You can open the Settings app and select Messages. Then, the option to Send as SMS will appear. If you want to disable the option to send iMessages automatically as regular text messages when you are offline, you can move the slider to the OFF position.
When you set the “Send as SMS” option to OFF, you can still send regular SMS text messages, even to recipients who don’t have an iPhone. Disabling the Send as SMS option only prevents your iPhone from sending iMessages as regular SMS texts automatically when you are not connected to the internet.
How to know when an iMessage is sent
When you send an iMessage, you will see that it has been received by the recipient because it will appear as “Delivered”. If they have enabled the option to “Send read Receipts”, you will see the message as “Read” as soon as they read it. You will also see the date when the message was read. If the message doesn’t show as “Delivered”, it means that the message hasn’t reached the recipient’s device. In that case, it is likely that there are issues that are preventing the iPhone from connecting to the iMessage server. This could happen when there is no internet connection available.
If the “Send as SMS” option is disabled, the iMessage will only be delivered when the device is connected to the internet. It is possible to make an undelivered iMessage to be sent as a regular text message, even if the Send as SMS option is turned off. If you come across issues trying to send an iMessage using the Messages app, you can tap on the undelivered message and hold it until you see the option to send it as a text message. This gets rid of the Send as SMS setting for this particular message.