jlc9779 wanted their SIM to be "good to go" on arrival at the airport so I doubt the process to register a local SIM card is really going to work. But with few other details it's hard to advise further.... Where they are coming from, what connectivity they need whilst they're here, how much data, etc. The lack of any details on the 3gsolutions website would concern me, the T&C's are very vague. Not knowing which network the SIM is issued from would be a concern, although I suspect it's HK. If the OP is coming from the UK, the CMLink SIM already suggested is a slam dunk easy option that is guaranteed to work provided the data allowance is enough.