Ur & Kazus

Head south to Ur. Your home village has 8 chests and 6 hidden items to pick up. Unlike FF1 and FF2, FF3 has hidden items in every town and dungeon. They won't show on the minimap, so you'll have to interact with pots, shelves, and grass patches to find them. This walkthrough covers all 61 so you won't miss any.

Ur

Enter Ur and visit the blue building to speak with Elder Topapa. He'll fill you in on Kazus to the south and Castle Sasune to the west. From there, head into the Inn on your right. Walk straight through the first door you see; the third pot inside holds a Potion (1/61). Back out and go upstairs. The second pot up there has another Potion (2/61). Exit the building.

Go south until you hit the trees along the flower bed, then take a right through a hidden passage and drop into the well. Chests 1, 2, and 3 are down here, all Potions (15-17/367). Climb back out and head north, staying to the far right along the tree line. At the end of the flowerbed, interact with the grass for a Potion (3/61).

Circle around the little lake and go north. You'll spot a path leading to an isolated house in the top-left corner of the map. Inside, the fourth pot at the bottom has an Antidote (4/61) and the second pot on the second row has another Antidote (5/61). Head to the top-right corner and check the rightmost candle; it opens a secret passage. Go up the stairs to find the last 5 chests: Longsword (18/367), Leather Armor (19/367), Cure (20/367), Dagger (21/367), and Leather Armor (22/367).

South of the house, there's a path between the trees. Take it to grab the last hidden item in Ur, a Potion (6/61).

Before leaving, visit the shops to upgrade your gear and pick up any spells you need (buy Cure from the magic shop if you missed the chest). But don't leave without talking to the old man in purple near the entrance. Give him a Potion and he'll hand over some Echo Herbs.

Kazus

From Ur, walk south to reach Kazus.

Everyone here's been turned into ghosts by the Djinn's curse. You can't buy anything yet, but there are 5 hidden items to collect.

Approach the first blue house but stop a few steps before it. Take a left into a narrow path through the trees. Keep going until you see a patch of grass on the left; check the tree there for a Staff (7/61). Continue north for a Mythril Helm (8/61) and Zeus's Wrath (9/61), then loop back out.

Step into the Inn. Speak with the ghost to the left of the flowers on the reception desk. This is Cid, FF3's airship engineer. He'll tell you his airship is parked in the desert outside town and offer to let you use it. While you're here, slip behind the counter past the glass of wine. On your left is a Potion (10/61).

The Blacksmith house sits directly above the Inn. On the first row, the second pot holds a Potion (11/61).

Before you leave, make sure you've got Killer Bee (#005), Werewolf (#006), and Berserker (#007) in your bestiary. The forest northwest of Kazus is the best spot to find all three. Once you've got them, head into the desert. You'll find Cid's Airship sitting in the sand. Board it and take the controls to lift off.