My wife will be in mainland for about three weeks and she need to connect her laptop to her employers vpn network. Pretty sure this connection will be banned in mainland. There was no "great firewall" on foreign SIM cards when we was in mainland in the past. Is it still possible to bypass the firewall with a Hongkong SIM card? Then I would get a mobimatter.com eSIM for her, 30GB for $30. This will be a Three HK eSIM, couldn't find any informations about the speed of this card. My Three UK SIM card was always very slowly when I used it abroad, how about the Three HK SIM?