Biopolymer foams were formed from aqueous solutions of carboxymethyl cellulose (CMC) and hydroxypropyl cellulose (HPC), whereby freezing-induced phase-separation and solvent removal yields robust foam structures that are elastic when wet and that are stable to repeated compression when fully saturated with water. Through mechanisms of phase-separation, pore formation, and covalent crosslinking, we discovered effective methods to prepare microporous CMC and HPC foams that resist gelation even when exposed to water for long time frames (at least months). Employing multifunctional carboxylic acid crosslinkers allowed the foams to maintain their integrity when dry or wet, while the presence of a-cellulose as an additive further augmented their mechanical integrity and provided a means to adjust elasticity. When covalent crosslinking was combined with the presence of CaCl2, and/or cellulose additives, the resultant CMC foams exhibited excellent aqueous stability for months or longer and withstood multiple compression cycles without loss of mechanical performance (i.e., by maintaining their porous foam structure). These hydrophilic CMC foams absorbed many times their own weight of water (30 g of liquid water per gram of foam) and were amenable to ion exchange, absorption/desorption of organic substances and heavy metals, and water uptake at levels that make them attractive materials for applications in water recovery. The amount of crosslinker employed in the HPC foaming process significantly impacted foam stability and water uptake, while polymeric crosslinkers enabled insertion of sulfobetaine zwitterionic moieties into the foams. Notably, the thermal transition characteristic of HPC solutions and gels proved operative in foam form, as seen in release of water from a saturated HPC foam using a combination of compressive and thermal mechanisms.