Traverse the Corrupted Lands
To traverse the Corrupted Lands, begin by going up the stairs and dropping off the ledge into the sand. Follow this path until you reach a dolphin, which you will mount. While on the dolphin, jump to hit all green crystals to collect Tetra. The primary objective is to restore water by activating water orbs or lanterns.
Immediately after mounting the dolphin, swim forward and activate all lanterns in the sand. There is a small patch to the left and a larger patch further ahead, surrounding a tower. After activating these, follow the path of water and fish up the hill. Branch off to the left to activate more lanterns. Continue following the path over the bridge with large statues in front of it.
In the Sacred River, exit the cave into the temple and go around the corner to the right. You will encounter a gap with a green air strip; use the Water Rail ability (by jumping three times) to cross. Once across, go up the stairs on the left and use Water Rail to float through the hanging gold lanterns. After gliding past the first set of hanging lanterns, go to the corner with a boulder and turn around. Use Water Rail to glide onto the shark statues and to the back wall where a dolphin statue holds a vase. On the ledge around the middle of the statue, go around the right side to find a secret shell. After activating the hanging lanterns, from the right side of the stairs, use Water Rail again to fly to the left.