The vast, untapped potential of the world's oceans is revealing groundbreaking advancements in human health and vaccination. Marine microalgae such as Nannochloropsis spp. and Dunaliella salina are emerging as vital sources for recombinant vaccine development. Various specific and heterologous genetic tools have been generated for Dunaliella salina and Nannochloropsis spp. To boost production of functional recombinant antigens and even the induction of immunoprotective responses. In humans, promising antigens produced in microalgae have shown potential in combating diseases caused by the Human papillomavirus, Human immunodeficiency virus, Hepatitis B virus, Influenza virus, Zika virus, Zaire Ebola virus, Plasmodium falciparum, and Staphylococcus aureus. For animals, microalgae-derived vaccine prototypes have been developed to fight against the Foot and mouth disease virus, Classical swine fever virus, Vibriosis, White spot syndrome virus, and Histophilus somni. Compared to the sources of other drugs, marine organisms offer unique advantages, including the ability to express complex antigens and sustainable production. Additionally, the ocean provides an array of bioactive compounds that serve as therapeutics, potent adjuvants, delivery systems, and immunomodulatory agents. These innovations from the sea not only enhance vaccine efficacy but also contribute to broader immunological and general health. This review explores the transformative role of marine-derived substances in modern medicine, emphasizing their importance in the ongoing battle against infectious diseases.