Sorry for the late and late updating!!!
Now, I
will talk about the Transportation to HKZBG whenever living in Kowloon, New Territories, Hong Kong Island or Islands. This blog can satisfy your needs♥
Accessible Bus Routes:

From Central 3B, 12, 13

From Admiralty 12A, 12M, 40M, 40P, 40

From Causeway Bay 23A, 23B

From North Point 23

From Lok Fu 103
Source:
http://www.lcsd.gov.hk/parks/hkzbg/en/how.php
My SuggestionSsssssssssss,,
Proposed Entrance 1: Caine Road / Glenealy
Target point: Animal ans Reptile house
How to get there:
Step 1: Take the bus to go to the Caritas Caine Road.
Step 2: Direction of the car off the line to the intersection
Step 3: Signs for turn right
How to get there:
13, 40M, 103
The back crossroads turn left to cross the road (Line to the left opposite the Caritas Centre), there are about ten meters on the diagonal line to bus stops
12, 12M
If you do not mind traveling more to get off, you can take No.12 in the entrance of Caritas to get back(Alighting Location: HSBC Main, Pedder Street -> Hong Kong Island Line, IFC 2) or No.12M (Again by the Admiralty, Central), it is estimated about 20 -25 minutes traveling time.
Proposed Entrance 2: Garden Road near McDonald Road
Target point: Bird Cages, Greenhouse Garden, walk down a road to Fountain
How to get there:

Admiralty Station Exit B Lippo Centre (Next to Taxi/Private carpark entrance)
Take

12A, Turn left into McDonald's Road, get off at 1st station
Proposed Entrance 3: Garden Road near Kennedy Road
 |
Main Entrance of HKZBG |
Target point: Main entrance with the fountain
How to get there:
3B, 12,23, 40, 103
Step 1: Get off at Kennedy Road stop
Step 2: Walk up to the nearby stairs--over 100 steps
Not Recommended!!!!!!
Take action to go to this Hong Kong Theme Park for leisure!!!!!!!!!!
P.S. Beautiful & Eye-catching video of HKZBG animals♥
Enjoy it♥
By Winnie Leung