Spoiler warning: this article may contain major plot or ending details.
After clearing Dark Crater and subsequently clearing three or more jobs, Manaphy will return and join the team. After subsequently passing three more days, Manaphy will tell the hero and partner about Marine Resort, unlocking the dungeon.
Gameplay
The jobs are ranked E, ★2, ★3, or ★4 by default, depending on the floor.
The floors are all large-sized in this dungeon, with a varying amount of rooms:
3-8 rooms on floors 1, 2, and 8
3-9 rooms on floors 4 and 5
3-10 rooms on other floors
3-13 rooms on floor 10
3-17 rooms on floor 9
There are 2-5 items on the ground and 4-7 buried in the walls. There are 2-3 starting enemies on floors 1 through 6 and 2-4 on later floors.
The IQ Booster activates on every even floor. The turn limit is 1000. Enemies in the dungeon have 150IQ. There is water in the dungeon. The weather is cloudy on floors 3 and 9, sunny on floors 4 and 8 and fog on floor 5.
As reported by Manaphy, Gummis are a common item in Marine Resort. Additionally, Gold Ribbon shows up very frequently in the Hidden Stairs item pool.
Pokémon encountered
Most of the Pokémon located here also appeared in Azurill's nightmare.
Each time the player enters a floor, only 14 of the species that can be found on a given floor will be chosen. The unpicked Pokémon's spawn rate will be added to whichever picked Pokémon is next in the National Dex order, going back to the beginning if needed.
The items are available either via Grab Bags in the Secret Bazaar (with 50% chance it contains an Oran Berry instead), or inside the Boxes in a Secret Room.
On most floors, the game will spawn 3 to 7 traps on the floor. On floors 1 and 7 it will spawn 2 to 5 traps instead, and on floors 2 and 8 it will spawn 3 to 6 traps instead. The game will spawn extra traps within a Monster House room.
