Istana Park is a small park on the edge of Orchard Road, easily accessible and close to Fort Canning park.
It’s a free local park and open all hours. I found it when walking from Clarke Quay up to Orchard Road, which is a lovely 20 minute walk. Alternatively, it’s next to Dhoby Ghaut MRT and also accessible on many bus routes.
When I visited, they had a lovely little Christmas display.
The water feature, pond and trellis screening is beautiful to see.