Microalgae and macro-algae recognised as strategic third-generation feedstocks for both liquid and gaseous biofuels, alongside high-value bioproducts like nutraceuticals and biofertilizers. The objective of this review is to evaluate the current technological landscape of algal biotechnology, examining diverse cultivation systems, conversion pathways, and the shift toward integrated biorefinery models. While algae offer significant environmental benefits—including high CO₂ fixation and non-competition with arable land—large-scale production remains pre-commercial due to prohibitive costs in cultivation, harvesting, and downstream processing. This paper highlights critical research gaps, such as the need for low-energy dewatering methods, robust strain engineering via synthetic biology, and the optimisation of wastewater-integrated systems. As the industry moves from a fuel-only focus toward diversified biorefineries, achieving cost-competitive and carbon-efficient algal biofuels at scale is still the central challenge for the coming decade.