The more stringent requirements for the environmental performance of marine fuels, stipulated by the ISO 8217:2024 standard, which also provides for the possibility of expanding the use of renewable resources in the fuel composition, makes the study of alternative fuels more relevant than ever. Residual marine fuels, which are a mixture of high sulphur residues, distillate and gas oil fractions, are well suited for the introduction of a biocomponent. In our work we investigated marine fuels consisting of asphalt, vacuum residue, atmospheric residue, hydrotreated vacuum distillate, hydrocracking residue and catalytic cracking and delayed coking gas oils with the addition of recycled used cooking oil. Quality parameters and hydrocarbon composition were determined for the fuel components and the biocomponent, as well as the main indicator of sediment stability of the colloidal fuel system – total sediment accelerated. It was found that with increasing the proportion of recycled used cooking oil in the composition of marine fuel, its density, viscosity, and sulphur content decreased. In addition, it was found that the introduction of recycled used cooking oil has a positive effect on the sedimentation stability of the fuel due to the triglycerides of fatty acids contained in it, which due to their surface-active properties stabilise the asphaltenes contained in the fuel.