This 75 floor dungeon is unlocked by purchasing the Calm Sea Friend Area. HM Dive and a Water Pokémon are required to enter the dungeon. The leader cannot be switched.
Two TMs unique to Pokémon Mystery Dungeon are found in this dungeon (Vacuum-Cut and Wide Slash).
| Name | Type | Level | EXP | Levels seen | Recruit Rate |
|---|---|---|---|---|---|
| Shellder | 25 | 1-8 | 12.2% | ||
| Omanyte | 30 | 1-9 | 8% | ||
| Krabby | 32 | 1-10 | 8% | ||
| Slowpoke | 25 | 6-14 | 12% | ||
| Seel | 18 | 6-14 | 3.9% | ||
| Spheal | 22 | 10-19 | 8.8% | ||
| Anorith | 26 | 14-23 | 8.7% | ||
| Vaporeon | 25 | 20, 30, 50, 60, 70 | N/A | ||
| Grimer | 20 | 20-29 | 12.2% | ||
| Omastar | 35 | 20-29 | N/A | ||
| Kingler | 35 | 26-35 | N/A | ||
| Slowbro | 27 | 30-36 | N/A | ||
| Carvanha | 27 | 30-39 | 8.9% | ||
| Starmie | 22 | 35-44 | N/A | ||
| Armaldo | 33 | 35-44 | N/A | ||
| Sealeo | 24 | 35-44 | -19% | ||
| Wailmer | 35 | 41-50 | 8.2% | ||
| Lapras (blue only) | 30 | 45-50 | 6.7% | ||
| Luvdisc | 30 | 45-54 | 8.6% | ||
| Dratini | 30 | 50-59 | 11% | ||
| Slowking | 38 | 50-59 | N/A | ||
| Dewgong | 35 | 55-64 | N/A | ||
| Octillery | 30 | 55-64 | -30% | ||
| Muk | 36 | 60-69 | N/A | ||
| Sharpedo | 35 | 60-69 | N/A | ||
| Walrein | 28 | 60-69 | N/A | ||
| Clamperl | 35 | 65-75 | 8.5% | ||
| Kingdra | 40 | 70-75 | N/A | ||
| Wailord | 40 | 70-75 | N/A |