Alternative fuels can help the maritime shipping industry to lower its emissions. However, there are commercial risks that surround the adoption of these cleaner fuels. A book & claim based carbon insetting initiative could reduce these commercial risks and accelerate the decarbonization of the maritime shipping industry. Carbon insetting is the process of funding an emission reduction within the sector where the emissions that are being compensated originate from, through the purchase of certificates. Book & claim facilitates the generation and trade of certificates for certain products & their properties. Combining carbon insetting with the book & claim chain of custody concept enables the generation and trade of scope 3 CO2 certificates for shippers when vessels bunker alternative fuels. Effectively enabling shippers that want their goods to be transported sustainably to pay the price premium for using alternative fuels, thereby facilitating change and sustainability in maritime shipping, without a change in logistics. The purpose of this master’s thesis is to understand how the concept of book & claim based carbon insetting can enhance the competitive position of the port of Rotterdam for the bunkering of alternative fuels. By simultaneously understanding what potentially the most effective way is to implement this concept at the port. This is achieved through a literature review, together with a workshop conducted for Port of Rotterdam Authority (PoRA) employees. The workshop results show that the participants have different views on how a book & claim based carbon insetting initiative should be approached. The participants’ answers covered a range, lying on two different ends of the spectrum for potential starting points. A book & claim based carbon insetting initiative at the port of Rotterdam can potentially enhance the port’s competitive bunkering position for alternative fuels. Implementing this concept in the port would create a clear demand stream for alternative fuels, which will enable the scaling of the supply of alternative fuels within the port, improving their affordability. Three frameworks were identified that each have their own approach to implementing book & claim based carbon insetting in the maritime shipping industry. These frameworks were evaluated based on six criteria, which were formulated from the results of the workshop. All three frameworks were evaluated for two scenarios based on the two different starting points addressed by the workshop participants. Based on the above research results, a business strategy has been formulated for the PoRA regarding book & claim based carbon insetting. This proposed business strategy consists of general recommendations and a range of possible approaches the PoRA could take to support the concept. Book & claim based carbon insetting for the maritime shipping industry is still in its infancy. It has the potential to lower the commercial risks surrounding the adoption of alternative fuels, accelerating the development of a market for sustainable shipping. In turn, accelerating the decarbonization of the maritime shipping industry while potentially enhancing the competitive bunkering position of the port of Rotterdam for alternative fuels if such an initiative is set up in the port.