Yes, you can forward calls to any telephone number which includes international destinations.
Some low cost non UK destinations (most landline numbers in mainland EU and the US) should be included to use with the free test credit that is automatically added to your account when you start, however if your call does not connect when testing then simply top up your account to pay for the international call forwarding leg of the call.
We recommend that non-UK destinations use VoIP/SIP instead of forwarding calls internationally. VoIP/SIP will allow you unlimited free inbound calls over the internet.
For call forwarding costs, please see our Call Rates & Bundles page and use the online rate checker.