It is estimated that a large amount of by-products are generated in the fishing industry. Some of these have shown to be of excellent nutritional quality. This work aimed to introduce the by-products generated by the sea bream processing industry as a new ingredient in the production of healthy and sustainable fish and seafood burgers. To this end, the bones, attached muscle and fins from sea bream filleting were treated to obtain flour from these by-products, which was used in the formulation of sea bream and shrimp burgers. Initially, a total of four burger formulations were tested: control samples (C), samples with sea bream and shrimp muscle + 10% by-product flour (BP10), samples with sea bream and shrimp muscle + 7% by-product flour + seaweed mix (sea spaghetti, kombu, nori and wakame) (BP7Sw) and samples with sea bream and shrimp muscle + 7% by-product flour + spirulina (BP7S). After a sensory evaluation with semi-trained panellists, the BP7Sw and BP7S formulations were discarded, especially because of their intense taste and colour. A sensory evaluation with the selected burgers (formulations C and BP10) was carried out with consumers using hedonic scales. The control burgers were highly acceptable, with values above 7 out of 10 for all attributes. The presence of the by-products caused a decrease in sensory acceptability. The odour and flavour attributes were evaluated with values of 7.4 and 7, respectively, but the overall acceptance was slightly below 7, mainly due to the colour attribute. It would be necessary to reduce the percentage of flour or to use some natural ingredient that could improve the burger colour. On the other hand, the use of this by-product flour could be interesting in battered fish products, where the dark colour of the by-products could be masked by the batter.