The call credit transfer service is available for Lebara Mobile UK customers and international call credit transfer is available for select countries. The list of countries you can transfer credit to are listed here.
Transfers are available to make in denominations of £2, £5 and £10. Credit transfers can only be used up to the amount of standard credit available in your account ( excluding any promotional credit). You can also use your plan allowance of data, voice minutes and SMS to make a transfer. Where plan allowance is used, the allowance will be deducted by 20%, 50% and 100% ( across data, minutes and SMS).
While roaming, specific charges may apply. Amount per transfer and number of transfers allowed per day may be limited. See full terms and conditions here