The former star is due to be driven under police escort to Tan Son Nhat airport in Ho Chi Minh City.
He is expected to have a ticket to London - but there are no direct flights to the UK, which allows him the option of buying another ticket when he changes planes.
His lawyer said: "He has served his sentence and the authorities in Vietnam will deport him. He does not have any sentence to serve in London. If he wants to stop wherever he wants to he can do that.
"If he wants to he can change flights."
He added: "The only problem is the countries he wants to go to, because he has to get a visa."
Sex offenders register
However, the lawyer said his client told him he wanted to return to the UK, had a ticket to London and was eagerly anticipating his release.
A Foreign Office spokesman said it was "a matter for Mr Gadd and the Vietnamese authorities" where Glitter goes after he is deported.
If he does fly back to the UK, the disgraced star will be met at the airport by police and required to sign the register of sex offenders.
He will then be subject to monitoring and will have to tell the police where he plans to live and if he plans to go abroad.
And he could also face an order prohibiting him from going near children or using the internet.