Navigating the protein fitness landscape is critical for understanding sequence-function relationships and improving variant effect prediction. However, the limited availability of experimentally measured functional data poses a significant bottleneck. To address this, we present a novel data augmentation strategy called fitness translocation, which leverages fitness landscapes from related proteins to enhance the performance of variant effect predictors on a target protein. Using embeddings from protein language models and by translocating the features within the sequence space, we transfer the fitness information from homologous protein datasets to a target protein to augment its dataset. Our approach was evaluated across diverse protein species, including IGPS orthologs, GFP orthologs, and SARS-CoV-2 spike proteins strains for cell entry and ACE2 binding. The results demonstrate consistent and substantial improvements in predictive performances, particularly for datasets with limited training data. Furthermore, we introduce a systematic selection framework for identifying the most beneficial protein datasets for augmentation and optimizing predictive gains. This study highlights the potential of related protein fitness translocation to advance protein engineering and variant effect prediction. The implementation of the method is available at https://github.com/adrienmialland/ProtFitTrans.