I recently had a 12 hour layover in Singapore on my flight from Brisbane, Australia to Koh Samui, Thailand.
Once I knew I had this stop over I quickly went to work searching the internet on things to do during this time. The stand out was the free tour of Singapore for long layovers.
My flight arrived at 8am Singapore time. I made my way through the maze that is Changi airport to find the registration desk in terminal two for the free tour. The next available tour was 3:30pm so I booked myself in.
This gave me 6 hours to kill before my tour started. I spent the next 2 hours exploring terminal 1 and 2 (Changi airport is enormous)
I eventually settled Infront of one of the many screens throughout the airport and watched an HBO boxing event for the next 3 hours.
Once 330pm arrived I headed to the free tour. We cleared customs as a group and jumped on a bus. (Very easy)
We spent the next 2 hours driving around Singapore getting off the bus multiple times to explore various parts of the city. See photos.
Once back at Changi airport we entered as a group through customers, once again a Very easy transition.
It was now dinner time so I set out to explore the many food courts to try some local food before my flight took off.
My 12 hour stop over wasn't wasted I got to see a little bit more of the world.
I see a lot of people in Changi airport sleeping or just sitting around waiting for their connection. Changi airport is massive. I highly recommend you explore it and if you have time check out the free Singapore city tour.