Seaside Cavern, often called Seaside by players, is a Water-type beginner dungeon located in Exbel, east of Seafoam Cove. It is unique for having locked stairs which must be unlocked using a Seaside Key to proceed to the next floor. The boss located at the end of the dungeon is Kingler.



Seaside Cavern consists of small, often elongated rooms with pathways which directs players to the next room. Walls are indigo in color and keen, whereas the floor tiles are sandy-beige. Small bodies of water are apparent throughout this dungeon. Slight darkness is present in the entire dungeon.


Seaside Cavern Pit

Upon reaching the Seaside Cavern Pit, Kingler is mad at the player for stomping around the dungeon and accuses you of taking his loot away. He will then proceed to fight the player.

Boss Drop

  • 50 Poké
  • Mystic Water
  • Water Stone
  • Mushroom

Before Fighting:

  • ARGHH! So it was you who was stoming around up there and stealing all my loot!
  • Do you really think I would let you go? Argh! Of course not!
  • Now, prepare to walk the plank!


Pokémon in bold are recruitable. Please visit the Recruitable Pokémon page for more information.

Icon Pokémon Floor Recruit Rate
079 Slowpoke BF1-5 12%
120 Staryu BF1-5 8.9%


Name Location Tile Hidden
Poké All Floors Floor No
Seaside Key All Floors Floor No
Apple All Floors Floor No
Leppa Berry All Floors Floor No
Oran Berry All Floors Floor No
Blast Seed All Floors Floor No
Geo Pebble All Floors Floor No

Dungeon Objective

The objective of this dungeon is proceed into the dungeon and beat the boss. This is also the the earliest dungeon whereby players can recruit Slowpoke and Staryu.


The player has to collect Seaside Keys located throughout the dungeon and use them to unlock the sealed stairway found on the 2nd, 3rd and 4th floor in order to progress. To unlock the stairs, the player must walk onto the stairs with the Seaside Key in the inventory. Once unlocked, the player must step on the stairs tile again to proceed to the next floor.


Locked stairs in a room.


  • Seaside Cavern was originally a part of PMU 6, and was re-added in PMU 7 as one of the four original dungeons.
  • When added to PMU 7, for about a year and a half it still had its premapped form, but was then remodeled into a random dungeon.
  • Seaside Cavern was one of the four original PMU 7 dungeons.
  • Pillager's Cove, west of the Seaside Entrance, appears to be an old hideout of Cap'n Kingler and his crew.


Pokémon Mystery Universe- The New Seaside Cavern

Pokémon Mystery Universe- The New Seaside Cavern

Seaside Cavern Playthrough

Early PMU7 Seaside Cavern Playthrough by taco pizza

Early PMU7 Seaside Cavern Playthrough by taco pizza