Duck meat enjoys growing popularity among consumers. Alternative protein sources to soybean are being investigated to eliminate genetically modified components from the poultry' diet. The aim of this study was to compare growth performance, quality of meat, and fatty acid composition in subcutaneous and abdominal fat from ducks fed a diet based on yellow lupin and rapeseed meal, sources of protein alternative to soybean meal (SBM). Ducks were allocated to different dietary treatment groups and reared for 8 weeks (N = 102 per group). Group A received a diet based on SBM, while group B was fed a diet based on yellow lupin with the addition of rapeseed meal. Both groups were divided into two subgroups, of male and female birds. Growth performance parameters and zoometric traits of ducks were monitored during the growth period. After 8 weeks selected birds were slaughtered and dissected (N = 10 per group). Carcass composition was calculated and selected traits of meat quality important for further processing were analysed. Subcutaneous and abdominal fat were collected to analyse fatty acid composition. The alternative diet had no negative effect on ducks' growth performance parameters and dressing percentage. The replacement of SBM with yellow lupin and rapeseed meal increased n-3 fatty acid content, which is important for consumers. In conclusion, SBM can be replaced with feed containing 60.10% of yellow lupin and 14.00% of rapeseed meal in concentrate. These sources of protein are mainly recommended for small poultry farms, which do not always have access to SBM and prepare poultry feed from their own crops.