Trainer Hill (Japanese: トレーナーヒルTrainer Hill) is a facility in Pokémon Emerald located just north of Mauville City, on Route 111. Much like Trainer Tower in the Sevii Islands on Pokémon FireRed and LeafGreen, Trainer Hill is a tower designed for Trainers to race and battle through quickly. The concept remains mostly unchanged from the Trainer Tower: each battle mode has a default time and if beaten, offers a rare in-game item as prizes. The player's Pokémon will not be healed between battles, though recovery items such as Revives and Potions can be used both during and between battles. Unlike Trainer Tower however, the prizes here vary depending on the time taken, and all battles conducted here are Double Battles (although the player can battle each of the two opponents separately in some rooms). Instead of different battle types, the modes here escalate in difficulty.
Battles conducted inside of Trainer Hill do not award experience or money. The level of the Pokémon used by Trainers will also match the player's highest-leveled Pokémon.
In the original Japanese release of Pokémon Emerald, Trainer Hill also serves as a facility with compatibility for the e-Reader, like Trainer Tower in Pokémon FireRed and LeafGreen. Cards from the Pokémon Battle e Emerald set can be used to modify the Trainers the player can battle, as well as the floor layout, and the top prize they can earn. The default layout of Trainer Hill in the Japanese version has two floors with the same Trainers on each floor for each playthrough. Scanning cards can increase this to a maximum of four floors. The set of Pokémon that each scanned Trainer will use is also dependent on whether they were scanned first or second for that floor.
The Trainers and individual floor layouts featured in the localizations are taken from the cards found in the Pokémon Battle e Emerald set.
Trainers with a PokéNav by their names will be registered in the Trainer's Eyes or Match Call function after the first battle, and may have a rematch with the player with higher-level Pokémon.
In the event that an odd number of cards are scanned, the game will place a preset Trainer alongside the last Trainer scanned, as two are always required for one particular floor. The amount of cards scanned will influence this preset Trainer:
if only one card is scanned, it will cause a Trainer to appear on the first floor;
three cards will make a Trainer appear on the second floor;
five cards will make a Trainer appear on the third floor;
seven cards will make a Trainer appear on fourth floor.
The preset Trainer is the same for each individual floor.