There is a separate musollah for muslimah and muslimin available at RWS (The Forum, Level B1) near to The Streats. 
Prayer mats and telekung are available. Qibla sign and ablution area provided as well. 

Contributed by Brother Jeffri

Please note that the unofficial prayer area at level 4R, near to the library no longer exists. 

There is a new unofficial prayer area at the staircase on level 3 of the carpark.

From the Serangoon MRT (CC13/NE12),
1. Take Exit G which will lead you to Level B2 of NEX.
2. Take the lift/escalator up to Level 3 of the NEX mall and walk towards the Fairprice Xtra (#03-42) Exit.  
3. On the left of the Fairprice Xtra (#03-42) Exit is the connecting bridge leading to the Carpark Level 4.
4. Walk down the bridge and turn right and walk till the end of the Carpark (near to the trolley bay). Please be careful of the vehicles. 
5. You will see a ramp leading down to Level 3 Carpark with more trolleys. Walk down the ramp and on the right of lot 195 is the staircase with sign 'Smoke Stop Lobby Staircase 10'. The unofficial prayer area is located just behind that door and shared for both muslimah and muslimin. 

There is a Qibla sign and a prayer mat available. Please bring your own telekung. 
For ablution, you would have to go to the nearest toilet in NEX mall before making your way to the unofficial prayer area.

The address of the restaurant is: #01-07 HometeamNS Balestier. 
There is a musollah in the restaurant, please note that this is only for customers. For more information, the musollah can be found in this facebook video at timestamp 2:17.

There is an ablution area inside the prayer room. Separate prayer room for men and women. No air-con, only fan. Please bring your own telekung and prayer mat just in case, as we are not sure if these are provided. 
For assistance, please ask the staff.

Contributed by Sister Nisaa