Transit visa 144 hours

Liz, if you plan just to visit Shenzhen and then return back to Hong Kong, your only option is to obtain a a visa on arrival at Lo Wu (Luohu) border crossing. This is 5 days Shenzhen visa on arrival and it comes at cost of 130 CNY that should be paid by card. You are advised to take a train to Lo Wu early, preferably even before 08:30 in the morning and to be at visa office at Luohu border crossing before the opening time of visa office. Visa office opens at 09:00. You need your passport and you will fill out a form. When you pay the fee, you will be granted a Shenzhen VOA. You can stay in Shenzhen for up to 5 days. You can return back to Hong Kong by taking any border crossing and any mean of transport, high speed train included. You cannot use 144 hour visa free transit here because this is not a transit. A Shenzhen visa on arrival is the way to go. Enjoy your journey.