The effect of microwave hydrodiffusion and gravity (MHG) treatment (over the range of 50 to 800 W) on the recovery of liquid phases with bioactive compounds from two edible brown seaweeds, and the corresponding colour characteristics, were studied. For comparative purposes, conventional distillation technique was performed. The potential application of the collected bioactive liquid phases in the formulation of functional hydrogels was evaluated. The obtained results indicated that liquid phases collected from both Undaria pinnatifida and Laminaria ochroleuca seaweeds MHG-treated at 300 W or selected optimized combination of microwave irradiation powers and times (CPT) exhibited the highest phenolic content or antioxidant capacities. The distillation methodology did not improve the antioxidant liquid features. No notable differences were identified in terms of colour of the liquid phases for both algae. Mechanical spectra and textural profiles of the selected hydrogels exhibited typical gel behaviour and suggested that liquid phases with the highest bioactive properties involves the hydrogels softening. It was found that the liquid phases collected by MHG technology from edible brown seaweed would be a suitable resource for the formulation of functional hydrogels with bioactive properties with potential development in food and other industries.