Hello there and welcome 🙂
All of our giffgaff phones are sold fully unlocked and have no network advertising so need no to worry about your handset locking.
See this handy giffgaff guide I have added for reference -http://community.giffgaff.com/t5/Getting-started/Buying-a-giffgaff-phone/ta-p/10441209
** Quoted from the guide above **
-Are giffgaff phones locked to giffgaff?-
" Not at all. We think you should be free to do what you like with your phone, and so every phone you buy from giffgaff is completely unlocked and will stay that way. This applies to iPhone, Android, BlackBerry, Windows Phone - the lot "
Hopefully this answers your question 🙂
- You can pop back if not though --