Operationalised in 2010, Institution B4 functions as both a prison and drug rehabilitation centre. It is a low-medium security prison housing both male penal inmates and drug abusers and has a capacity of 1,584 inmates.

Institution B4 operates various training facilities allowing inmates to learn new skills to enhance their employability. These include:

“Hope Café” where inmates undergo hands-on training in culinary skills and food and beverage operations.
Logistics workshop where inmates undergo training in warehouse and logistics management.
“Visual Arts Hub” where artistically inclined inmates receive training in different art forms.

The institution is also a pre-release centre for drug abusers to undergo pre-release programmes to support their reintegration back into society. In collaboration with Yellow Ribbon Singapore, job placements and employment assistance are provided for them prior to their release.