In 1892, 14 British pillar boxes were installed in Hong Kong and until the handover to China in 1997 thousands more serviced the territory. What is left are painted green and it was reported in October 2015 that Hongkong Post planned to put a plate over the remaining 59 post boxes with royal insignia that are still in service to 'avoid confusion'.
There haven't been any riots over post boxes yet but it's not a bad idea to visit some of them before they are gone. Two are very difficult to reach - one is in the closed frontier area with China and one is in a mental hospital.
There are 73 British era post boxes left in Hong Kong, 64 in service and 9 on display:
You can find them all on the Hidden Hong Kong Map
55. GRV - Magnolia Road, Yau Yuet Tsuen (Wall)
91. GRV - Hong Lee Road, Crocodile Hill (Pillar)
110. GRV - Tai Po Road (Wall)
143. GRV - Shek Pik Reservoir Road, Lantau (Wall)
235. GRV - Lei Yue Mun (Pillar)
256. GRV - Sok Kwu Wan, Lamma (Pillar)
227. GRVI - School Road, Cheung Chau (Wall)
487. GRVI - Palm Springs, San Tin (Pillar, not owned by the Post Office)
239. Scottish Crown (Oval)
9. ERII - Ha Tsuen, Yuen Long (Wall)
35. ERII - Yau Tam Mei Village, San Wai (Wall)
38. ERII - Lok Yip Road, Fanling (Wall)
66. ERII - Sai Kung Market (Wall)
66. ERII - Cheung Chau Ferry Pier (Pillar)
90. ERII - Kwun Tong Road (Pillar)
117. No Royal Insignia - Pui O, Lantau (Wall)
150. No Royal Insignia - Tai O Tin Hau Temple (Wooden Box)
157. No Royal Insignia - Peace Avenue (Wall)
245. No Royal Insignia - Sheung Pak Nai (Wall)
262. No Royal Insignia - Keung Shan, Lantau
21. VR postbox now in the mini museum on the ground floor of the General Post Office in Central.
25. VR - Retired pillar box in the Hong Kong History Museum, originally located at the junction of Waterloo Road and Portland Street in Yau Ma Tei.
GRV - Retired King George V wall box on display in the Hong Kong History Museum in Tsim Sha Tsui.
60A. GRVI - in the wall of Stanley Post Office, no longer in use.
152. ERII - Lamp post-style postbox now in the mini museum on the ground floor of the General Post Office in Central.
ERII - Ocean Park, Wong Chuk Hang (Pillar) - a genuine pillar box but not in service, part of the theme park's Old Hong Kong Street attraction.