Hi @ChrisPB, 

This is a great question! Would love to explain more about this. 

Yes, by default you are provided with only a complimentary toll-free number when SMS is first enabled in your account. If you are looking to send to subscribers in Australia and/or the UK, you can additionally activate a free alphanumeric sending number. It is very important to note that you will need to activate your alphanumeric sender ID before you begin collecting consent for Australian or UK phone numbers, or else the consent will not be stored on the customer profile.  If you have no plans to send to US or Canadian recipients, you can choose to release your toll-free number. However, this shouldn't be necessary as the number is free of charge - hanging on to it shouldn't make any different in your billing or sending.

Some key differences between alphanumeric sender Ids and other phone types include the following:

• Alphanumeric IDs cannot receive inbound messages. This means you cannot engage in 2-way messaging, and also means that you cannot collect consent via custom keywords or click-to-join forms
• Because these sender IDs cannot receive inbound messages, you cannot enforce double opt-in
• Messages sent from alphanumeric IDs will contain an unsubscribe link as users cannot text STOP to opt-out
• Alphanumeric IDs can send SMS only; they do not support sending MMS

Additionally, a single SMS message sent to an Australian recipient will use 3 sends from your allotted send balance.  This means that a longer message that sends as 2 SMS messages would incur a cost of 6 sends per recipient. 

I’d recommend checking out these other Community posts to gain further insight into the topic of SMS in Australia!

Best,

Taylor