Finally got my android phone from the UK unlocked today! So I could finally have a 3G phone here in HK. Yay! The HKD250 was well spent!
If like me, you do not possess a tech-savvy boyfriend who is at your command to unlock your phone, this is the place to do it in Hong Kong: Sin Tat Plaza or 先達廣場 at Mongkok. (And no, they don’t unlock phone at the Wan Chai Computre Centre. Believe me, I’ve tried.)
Outside of Sin Tat Plaza
The inside of Sin Tat Plaza. It's FULL of small shops like these, buying and selling second-hand phones (quality varies), fixing and unlocking phones.
Address: Sin Tat Plaza, 83 Argyle St, Mongkok. Kowloon.
Direction: Get off Mongkok MTR, exit at D2, and walk 5 min.
Abby in Hong Kong 
Abby,
Any specific shop in Sin Tat to unlock phone?
Hello Marcelle! I don’t really recommend any specific shop. Definitely ask around and compare prices. The first few places I asked actually told me my phone couldn’t be locked, but I was eventually able to find a place that could do it. :) So good luck!