Conductive　hydrogels　have　emerged　as　fascinating　materials　for　flexible　electronics　because　of　their　integrated　conductivity,　mechanical　flexibility,　and　the　possibility　to　introduce　several　smart　functions.　However,　the　swelling　of　hydrogels　in　aqueous　environments　significantly　reduces　their　applicability　where　contact　with　water　is　unavoidable.　In　this　study,　a　physically　cross-linked　composite　hydrogel　is　proposed,　that　is　transparent,　highly　stretchable,　anti-swelling,　capable　of　autonomous　self-healing,　adhesive,　and　anti-freezing.　The　hydrogel　is　synthesized　through　a　simple　one-step　photopolymerization　in　a　novel　deep　eutectic　solvent　(DES)/water　system.　Dynamic　physical　interactions,　including　hydrophobic　interaction,　hydrogen　bonding,　and　electrostatic　interactions,　confer　remarkable　transparency　(92%),　self-healing　capability　(up　to　94%),　good　adhesion　to　a　wide　array　of　substrates　(91　to　199　kPa),　high　toughness　(1.46　MJ　m-3),　excellent　elongation　at　break　(up　to　2064%),　and　resistance　to　swelling　in　water　(equilibrium　swelling　ratio　of　3%　in　water　for　30　days)　even　in　solutions　at　different　pH　(pH　1-11),　and　in　other　solvents.　The　incorporation　of　a　DES　contributes　to　exceptional　anti-freezing　performance.　The　transparent　sensor　achieves　multifunctional　sensing　and　human　motion　detection　with　high　sensitivity　and　stability.　Notably,　the　sensor　demonstrates　information　transmission　underwater　through　stretching　and　pressing,　showcasing　its　immense　potential　in　underwater　flexible　devices.　In　this　study,　a　physically　cross-linked　composite　hydrogel　is　proposed,　that　is　transparent,　highly　stretchable,　anti-swelling,　capable　of　autonomous　self-healing,　adhesive,　and　anti-freezing.　The　hydrogel　is　synthesized　through　a　simple　one-step　photopolymerization,　and　its　use　as　multi-functional　flexible　sensor,　capable　of　detecting　a　series　of　human　movements,　and　also　suitable　for　underwater　communication　is　demonstrated.　image