Phantom Hourglass has no Pieces of Heart. Every extra heart comes from a whole Heart Container. Link starts with three hearts. You earn seven Heart Containers by beating the bosses on the main quest, and six more from minigames, sidequests and shops.
Boss Heart Containers (7)
- Blaaz (Temple of Fire, Isle of Ember): in the room past the boss arena.
- Cyclok (Temple of Wind, Isle of Gust): appears after the fight.
- Crayk (Temple of Courage, Molida Island): in a chest after the fight.
- The Cubus Sisters (Ghost Ship): in a chest after the fight. If you leave without it, it's sent to you by mail.
- Gleeok (Temple of Ice, Isle of Frost): in a chest after the fight.
- Dongorongo (Goron Temple, Goron Island): in a chest after the fight.
- Eox (Mutoh's Temple, Isle of Ruins): in a chest after the fight.
Other Heart Containers (6)
- Shooting Range (Molida Island): once you have the Sun Key, play the Bow shooting game on Molida Island and score 2,000 points or more.
- Maze Island (Northwestern Sea): win the Treasure Maze on Expert. You have to clear Beginner and Normal first, and you need the Grappling Hook.
- Fishing (Bannan Island): once the Old Wayfarer on Bannan Island has given you the Fishing Rod, complete his whole series of fishing challenges.
- The Traveler's Ship: after you reach the Northwestern Sea, look for the traveler's ship the Prince of Red Lions and play the owner's sparring minigame. Land 100 hits and he gives you the Heart Container.
- Beedle's Masked Ship: Beedle's special Masked Ship sells a Heart Container for 1,500 Rupees.
- Island shops: after you've bought the bigger Bombchu Bag, the island shops (such as Mercay Island's) stock a Heart Container for 2,000 Rupees. Only one is sold.