The Slime Collection quest in Sailor Piece requires you to locate seven Slime Pieces hidden across different islands. Completing this quest unlocks the ability to craft Slime Keys, which are essential for spawning the Rimuru boss on Slime Island. Each piece is tucked away in a specific spot—some behind trees, others on rooftops or near landmarks—so knowing the exact locations saves time.
Quick answer: Accept the Slime Collection quest from the Slime Key Crafter NPC on Slime Island, then visit Desert Island, Snow Island, Starter Island, Jungle Island, Shibuya Station, Hueco Mundo, and Shinjuku Island to collect all seven pieces.
Starting the Slime Collection Quest
Travel to Slime Island and head to the cluster of buildings near the center. Look for the Slime Key Crafter NPC and interact with them to receive the Slime Collection quest. The quest description reads "Find seven slime pieces across the map in order," and you can begin collecting immediately after accepting it.
Slime Piece #1: Desert Island
Teleport to Desert Island and run toward the large dragon fossil visible on the map. The first Slime Piece sits between the bones of the fossil. Walk up to it and collect it to mark the first piece complete.
Slime Piece #2: Snow Island
Head to Snow Island and locate the igloo with two small shacks nearby. Run past the shacks and jump toward the tree directly in front of you. The second Slime Piece is tucked behind this tree. Collect it and move on to the next island.
Slime Piece #3: Starter Island
Use the portal to return to Starter Island. Climb onto the roof of the building on your right as you enter the island. From the roof, jump to the branch of the nearby tree. The third Slime Piece rests on this branch. Grab it and prepare for the next location.
Slime Piece #4: Jungle Island
Teleport to Jungle Island and look for the tall watchtower-like structure. The fourth Slime Piece is placed on the roof of this tower. Climb or jump up to the roof, collect the piece, and continue to the next island.
Slime Piece #5: Shibuya Station Island
Travel to Shibuya Station Island and sprint to the far end of the island, running past the Yuji boss spawn area. You will reach a building with black panels on its exterior. The fifth Slime Piece is located in the corner of this building. Collect it and move to the next island.
Slime Piece #6: Hueco Mundo
Use the portal to reach Hueco Mundo. Once you arrive, look to your left for a pair of tall towers standing next to a domed building. The sixth Slime Piece is hidden between the bases of these two towers. Walk between them to collect the piece.
Slime Piece #7: Shinjuku Island
Teleport to Shinjuku Island for the final piece. Jump and dash over the building on the right side of the island until you spot a withered tree. The seventh and final Slime Piece sits on this tree. Collect it to complete the quest.
Completion Confirmation
After collecting all seven pieces, a notification appears on screen: "Slime Quest completed! Craft is now unlocked." This confirms that you can now craft Slime Keys at the Slime Key Crafter NPC on Slime Island. Your quest progress is saved, so you do not need to recollect the pieces if you exit the game.
Crafting and Using the Slime Key
Return to the Slime Key Crafter NPC on Slime Island to craft a Slime Key. Each key requires two Slime Shards, which drop from Slime Warriors (Level 8000 enemies) on Slime Island. The drop rate is low, so expect to defeat multiple enemies before gathering enough shards. Once crafted, the Slime Key is used to spawn the Rimuru boss on Slime Island. The key has no other known use in the game.