Efficient extraction of bioactive compounds from red lobster by-products is crucial for maximizing their nutritional and economic value. This study compared high-hydrostatic pressure extraction (HHPE), ultrasound-assisted extraction (UAE), and conventional extraction (CE), assessing the yield and bioaccessibility of carotenoids (astaxanthin, beta-carotene, lycopene), antioxidants (DPPH, FRAP assays), and minerals (sodium, magnesium, potassium, calcium). HHPE and UAE significantly enhanced carotenoid extraction (p < 0.05), with UAE yielding the highest astaxanthin (3.61 mg/100 g FW) and HHPE producing the most beta-carotene (0.64 mg/100 g FW). HHPE also significantly increased antioxidant capacity (38.04% increase over CE, p < 0.05). Despite reduced bioaccessibility after in vitro digestion, HHPE and UAE represent sustainable methods for recovering valuable bioactive compounds, improving the nutritional profile of red lobster by-products.