This study employed a combined approach of untargeted UHPLC-HRMS and targeted GC-MS analyses to investigate the effects of different cultivation media on the growth and bromoform production of Asparagopsis taxiformis tetrasporophytes. Growth performance and metabolic profiles were analyzed under various nutrient conditions, including PES, F/2, Walne, and a control medium. Significant variations in growth rates and metabolic compositions were observed across the media. Multivariate analyses revealed distinct clustering patterns, with PES and F/2 forming separate clusters from Walne and the control, indicating substantial differences in metabolic makeup. The PES medium, with its optimized micronutrient ratios, supported the highest growth rates and unique metabolic signatures, while F/2, though slightly less effective, offered a more cost-effective alternative for large-scale cultivation. Significant metabolic pathways were upregulated under PES, suggesting optimal conditions for A. taxiformis growth and metabolic activity. Targeted GC-MS analysis revealed that tetrasporophytes grown in PES exhibited significantly higher bromoform levels-up to 12,695 μg/g-compared to gametophytes and other seaweeds. This underscores the superior growth performance and bromoform production in PES, while highlighting the importance of considering both performance and cost in cultivation strategies aimed at methane mitigation.