Sending International SMS or Text message from Australia
To send a message to an International number you need to +CountryCode before the number, and remove the leading zero.
eg: Using the Mobile number of 0414 141 414
0414141414 would need to be entered as ‘+441414141414’ using the country code of +44 for UK
The + sign is important
Cost of Sending International SMS or Text message from Australia
Prices as at January 2015
Optus:
How much does it cost to send an international SMS?
For Postpaid Mobile, international SMS is charged as per your rate plan per message sent up to 160 characters.
For Prepaid Mobile, international SMS is charged at $0.35 per message sent up to 160 characters (excludes Connect 4 Less)
http://www.optus.com.au/shop/mobilephones/internationalcallingrates/sms
Vodafone:
Telecommunication Category Advert
What it costs
On most plans and prepaid recharges, international TXT sent from Australia are charged at the same rate as standard TXT.
You can check your plan details in My Vodafone.
365 Day Plan costs 28c per International TXT (Up to 160 characters) (5c per TXT delivery notification message)
TXT sent while international roaming are charged as roaming TXT.
http://support.vodafone.com.au/articles/FAQ/Sending-and-receiving-international-TXT-messages
Telstra:
Costs
$0.50 per Text (SMS) per recipient to any standard international number
https://www.telstra.com.au/mobile-phones/plans-and-rates/calling-overseas-from-australia
Amaysim is free to text and phone UK.
Not on all of the Amaysim Plans. Their prepaid plans and the $19.90 pm plan quote:
International talk and text:
From 6c/min standard calls, 25c per standard SMS, 75c per standard MMS
Local (in Australia) Text:
12c per standard SMS, 49c per standard MMS
It is still cheaper than the main three above.
The more expensive plans do offer free texts to China, Hong Kong, India, Malaysia, New Zealand, Singapore, South Korea, Thailand, UK and USA. Priced from $24.90 per month.
amaysim plans