Pile foundations driven into soft, consolidating soil layers are at risk of negative skin friction (NSF) or downdrag. This phenomenon is due to the settlement of the surrounding soil exceeds that of the pile, resulting in a reduction of the pile’s load-bearing capacity. This study focuses on a site within the reclamation area of Semarang, where the pile is subject to NSF. Two spun pile foundations with a diameter of 600mm were embedded into the area, one coated with bitumen and the other uncoated. Both piles were instrumented with fiber optic sensors to measure strain along the pile shaft during loading test and periodic readings were taken over time. This research aims to investigate the effectiveness of bitumen coating on the pile shaft by comparing the value of NSF between the two piles. The result of load transfer curve analysis for both piles indicate that the NSF values for the bitumen-coated pile are lower than those for the uncoated pile.