Call forwarding to overseas number

[Chuakh]

I want to set up call forwarding to a non UK number because I will be travelling and using a phone with a local number but I still want to receive any calls to my UK number. I have an iPhone 15 and am on a pay monthly plan. When i turn on call forwarding and enter the non UK number, the call forwarding option gets automatically turned off. I know it works because i have tested it with a UK number. 

Is there a way to do this, or does Three disable that function?

[PeteG]

Hello.

You can only call forward to UK numbers. 

Whenever you are call forwarding, you are essentially placing a call. The person is calling you, and the network is following the instruction and placing a call to the number you choose and connecting them.

If call forwarding was allowed to be made to overseas numbers, you would be getting charged for making an international call every time some one called your number. 

Pete.