Harvest Moon: Echoes of Teradea islands are a large part of exploration, because Teradea is surrounded by water and the map is a tall north-to-south layout. Four of them are separate remote maps, and the mainland has offshore land of its own.
Harvest Moon: Echoes of Teradea islands and the four remote maps
The four separate remote island maps are Finter Island, Sprummer Island, Ancient Island and Treasure Island.
The mainland map also has its own offshore land: Bloomfield Island, Horseshoe Islands, Tornado Island, Spring Blossom Islands, Western Islands, Eastern Islands, Sage's Territory, Beast King's Territory, Brown Bear's Territory, Ice Block Territory, Rock Shell Island, Eve's Calm Island and Uncharted Territory.
The Complete Map achievement — "Unlocked all maps including Remote Islands" — is the completion goal for them all.
The four nautical charts
Four Uncharted Territory Nautical Charts are scattered across the world map, and they are what unlock the Uncharted Territory area:
- One in a Maplehill chest, 161 m north of Maplehill Town.
- One in the Harvest Goddess Forest at Primordial Coast, 126 m northwest of Forest of Echoes West Area.
- One in Bloomfield at Garland Great Falls, 176 m west of Spirit Tree of Spring.
- One in the Great Lava Cavern, 253 m east of Lava Cavern East.
A fifth chart is a different thing: the Sprummer Island Nautical Chart is in the silver chest on the cliffs behind the warp statue next to Nera's pond on Tornado Island, and Shima needs that one to fix her map and locate the marooned fisherman Art. The full list of fast-travel stops that reach these places is on the warp statue page.
Tornado Island and the Guardian
Tornado Island is the one the story starts on. It is also called Breezy Island: local legend says a fish called the Guardian lives there and that anyone who reels it in is granted a wish.
You arrive to find it renamed because of the sea tornadoes that never stop, and it is where you catch the Guardian and meet Nera, the Tidewind guardian spirit. The Breezy Hot Springs sit 186 m north of it, the island has a warp statue, and the sea tornadoes that block it are the reason Tidewind's storms never clear. Breezy Island also has the Great Breezy Cavern, which holds two Silver Ore nodes.
The catch itself is the hardest in the game, and how to land it is on the fishing page.
The chest-run islands
Ancient Island and Treasure Island are chest runs. A chest on Ancient Island rolls Ancient Bronze Coins, Egg or Sunflower Seeds and refills every 5 days. The chests on Treasure Island and in Uncharted Territory roll Ancient White Gold Coins, Silkie Egg, Araucana Egg, Ancient Gold Coins, Ancient Silver Coins or Sunflower Seeds, and refill every 15 days.
Uncharted Territory also has its own fishing spots with Sardine, Saffron Cod, Sea Bass, Anchovy, Round Herring and Rock Bream, plus Jumbo Mushroom, White Truffle, Oyster, Large Clam, Akoya Pearl Oyster, Coconut and a Bengal Tiger.
Sprummer Island has a campsite where the Traveling Merchant can set up, a story-event treasure chest, and the rarest animal in the game: the Iriomote Cat has a single spawn point on Sprummer Island and only appears after 7 PM.
Two island detours worth knowing
Across the Meridian of the Great Sea, west of the Tidewind Campground, you can walk through shallow water to Castaway Coast — and on full-moon nights you can cross the shallow meridian all the way to Star-Fallen Islet and Rock Shell Island, each of which has a Power Wisp Statue, with a treasure chest on the larger Rock Shell Island containing 10 Minced Fish bait.
Full-moon crossings are the only way to reach those two, so it is worth checking the moon phase before you write the trip off. The chest contents are on the treasure page.