The Hydro Gates are very large, oval-shaped (sometimes round) rings with yellow and black stripes and an inner rim that glows cyan. In most cases, they are embedded in the ground with large sockets that extend up the rims: Others are held up by suspension from above.
The Hydro Gates can be found in Cliff's Excavation Site, Abandoned Research Facility, Bygone Island and Crater Lake. In gameplay, they allow the player to walk and run across water surfaces in areas with Hydro Dash without losing Rings and Robot Scrap. As such, they can always be found at the edge of large bodies of water. By passing through a Hydro Gate, the playable characters will be surrounded by an energy field that let them perform Hydro Dash. This technique will last until the player stands on solid ground again.