Hi Caro,
Here's a contact for Rockclimbing in Singapore:
Singapore Armed Forces Recreational Arm: 6788-8401
1A Tampines St. 92
Check this list as well:
http://www.rockclimbing.com/routes/list ... StateID=20
There is great rockclimbing in Bukit Timah Nature reserve, opposite the dairy farm there. There's 2 sites as far as I know, Hindhede Quarry in the Bukit timah reserve (tough routes) and the dairy farm one, which is much easier, it is near the
condos there at Dairy farm.
In the weekends you should just go there, there will be lots of enthusiasts climbing, just ask them as well?
Eric