As a significant contributor to carbon emissions, global logistics companies are under scrutiny from various stakeholders, and respond by disclosing carbon-related information in the form of carbon reports. Carbon disclosure is, however, a mainly voluntary practice that allows for a broad range of interpretation from the management field, which leads to different approaches to the measurement and reporting of carbon-related information. From a theoretical perspective, these different carbon-disclosure approaches in global logistics companies can be attributed to the underlying construct of competing logics, namely the market and the sustainability logic. While competing logics are frequently discussed in the current literature, little is known about their influence on shaping carbon-disclosure practices. The aim of this paper is to examine the similarities and differences in the measurement and reporting of carbon-related information in order to capture the underlying logic that drives carbon-disclosure behaviour in the global logistics industry. We adopt an interpretative content analysis approach and examine the carbon-related information using the Carbon Disclosure Project (CDP) reports of DHL, FDX and UPS. The analysis reveals significant differences in the applied carbon-disclosure strategies, as well as in the degree of transparency between the three companies. The results also indicate that the carbon-disclosure practices of FDX are dominated by a market logic that emphasizes the economic benefits of carbon reductions, while DHL and UPS have prioritized the sustainability logic to gain a competitive advantage.