Fatigue is a significant concern in the offshore oil and gas industry, posing risks to both resources and lives. This study aims to assess fatigue levels among daily trippers on offshore platforms and compare them across different job roles. The Offshore Fatigue Assessment Application (OFAA) was developed to measure fatigue in Malaysian offshore workers, focusing on alert response and lapses. A total of 51 participants were involved, with 31 in Crew A and 20 in Crew B. Based on the results, Crew A exhibited fatigue, with only 3 out of 12 data collection points showing an average reaction time (RT) below 500 ms, mainly during post-work periods. Crew B also experienced fatigue, with only 1 out of 12 data collection points showing an average RT below 500 ms, occurring during mid-work. While Crew B displayed fatigue during pre-work and mid-work, they generally maintained alertness during their sessions. Overall, Crew A consistently faced lapses in alertness, while Crew B showed fatigue during pre-work and mid-work but remained alert during their sessions. These findings highlight varying fatigue levels among offshore personnel, emphasizing the need for targeted fatigue management strategies in this industry. © 2024 American Institute of Chemical Engineers.