For those interested in accessing other terminals we decided to test it once and for all. I checked in online for my flight, departing from T4 and printed my boarding pass.
I was
not allowed to clear immigration in either T1/2/3. This was confirmed by the immigration shift manager in the operations centre that evening. However - all is not lost.
The process that
is allowed by CAG and immigration is to proceed to T4, pass through immigration and security. Then proceed by airside bus to T2.
The only problem is that there is no signage - it's completely hidden - as if Changi don't want T4 passengers leaving
Here's a map of how to the find the bus ("You Are Here")
Use the lifts to go down. The security will give you this attractive T4 sticker to wear and guide you through to the arrivals hall and then onwards into a small waiting area for the bus. It comes every 7 minutes.
You will arrive in the immigration hall of T2. The Skytrain to T3 is just upstairs. The Skytrain to T1 is opposite side of the terminal but about a 5-minute walk.
On the way back, the bus is well signposted and departs from next to gate F51 in Terminal 2.
Total travel times:
T4-T2: 19 minutes
T4-T3 (via T2): 24 minutes
Return:
T3-T2: 9 minutes
T3-T4 (via T2): 19 minutes
T3 times are taken from standing outside "Charles and Keith" where, opposite, they are about to open an "Irwins"!
Our T4 review will be updated accordingly and can be found
here with our Cathay Pacific T4 Lounge review
here and our T4 Blossom Lounge review
here