Amaterasu cannot use them until she tosses a Mermaid Coin into them. Her first Mermaid coin is obtained in Sasa Sanctuary from Mr. Bamboo after she battles Gi. After this, Mermaid Coins are available for sale from merchants or can be found in treasure chests. However, after Amaterasu obtains Fountain, she can teleport between Mermaid Springs without using a Mermaid Coin.
Mermaid springs can be found mainly through ponds and smaller pools of water, with a green light shining up from the surface. They are inaccessible until Amaterasu has revived the Guardian Sapling of the area with the Mermaid Spring, and even after this, she typically must clear a nearby obstacle such as a Devil gate or Digging minigame before they appear: if not, she must at least have been within line of sight of the spring and close enough that the whirlpool effect was visible, or it will not appear on the map. They are also visible on the map screen in the main menu. There are nine Mermaid Springs in all.
An alternative method of teleportation is the use of Mist Warp on Ultimate Origin Mirrors. These are generally favorable over Mermaid springs since there are far more Ultimate Origin Mirrors than there are springs, and the mirrors allow travel to be quicker and strategic. There are, however, some places that only the springs can reach, so they do have some use (the top of Catcall Tower, Sei'an City, etc.). They are also the best means of transportation before obtaining the Fog Pot required for Mist Warp.
Mermaid Springs are absent in Ōkamiden and as such, can not be used for warping. Instead they appear to be normal springs or ponds without the characteristic green light. Despite this and the inability to use Mist Warp, Chibiterasu can still warp between areas and through time via Ultimate Origin Mirrors by using Kagu's Charm.
- Shinshu Field: Clear the Devil gate near Onigiri-Sensei's Dojo.
- Agata Forest: At Hitoshio spring, located up the hill near the merchant.
- Taka Pass: Clear the Devil Gate near the waterfall in the main field.
- Sasa Sanctuary: Found in the hot spring behind the inn after restoring water to it and obtaining Waterspout.
- Ryoshima Coast: Clear the Devil Gate near the entrance to North Ryoshima Coast.
- Sei'an City: In a pond near Benkei's permanent fishing spot.
- North Ryoshima Coast: In the pool near the waterfall with the statue of Kabegami at its base.
- Catcall Tower: On the top floor of the tower.
- Dragon Palace: Complete the digging minigame in the dancer's garden.
- Kamui: Found near the Divine spring with Blockhead Grande, after clearing a Devil gate.
- When Amaterasu swims into the pulsating wave of the Mermaid Spring, she retain breathing capability, as if that the Mermaid Spring itself allows breathing underwater like in the Dragon Palace
- Even though that teleportation between Mermaid Springs are directly transporting Amaterasu into the water, standing above water on Lily Pads or equipping Water Tablet allows the use of both Mermaid Coins and Fountain.
- Small puddles that resemble Mermaid springs can also be found in Madame Fawn's house, the Water Dragon, and Oni Island. However, these do not teleport but instead heal Amaterasu's Solar Energy and Ink Pots.