They process thousands of vehicles daily - and thousands more on foot with passports in hand - checking for contraband items and clearing travellers through immigration.
Round the clock, officers from the Immigration and Checkpoints Authority (ICA) stand guard in shifts at Woodlands Checkpoint, helping to keep Singapore's borders safe.
Every day, more than 280,000 commuters pass through immigration at Woodlands - one of two land checkpoints in Singapore - making it one of the busiest land checkpoints in the world.
"There is never a typical day for ICA officers over at Woodlands Checkpoint," said Deputy Superintendent Nazeera Ebrahim, 47.
"We have found contraband items, such as cigarettes, and we even get animals like tarantulas and other exotic pets," said the assistant commander of ground operations at Woodlands Command. She has worked at ICA for 26 years.
Officers have to always be on their toes to properly manage the flow of vehicles and pedestrians, said DSP Nazeera.
How do they handle the burgeoning volume of not only human traffic but also cargo passing through?
Watch the officers at work in the first episode of Singapore Works, a new video series about the people and processes behind the scenes that enable Singapore to function seamlessly.