Originally Posted by
rkkwan
It is not impossible, but not proper. When you arrive at HKIA on the ferry, you'll already be airside. You need some sort of escort to get back to the ARRIVALS level and then clear HK Immigration. Most people having to get back into Hong Kong will ask for escort at their airline lounge.
I'll take your words a step further and state that this is HIGHLY frowned upon by the ferry people.