The long-awaited Full Moon Update has arrived in Royale High, bringing with it a brand-new realm called Luna Lagoon, limited-time Mermaid Trading, and a hidden chest containing an exclusive transformation item. This guide covers everything you need to know — from how to access Luna Lagoon to where to find the secret chest and what rewards await you inside.
Royale High Luna Lagoon Update Guide 2025 October
Update Name: Full Moon / Luna Lagoon Update
Event Duration: 3 Days (During the Full Moon cycle every month)
Key Features:
New Luna Lagoon Realm
Mermaid Trading system
Secret Chest with a special transformation item
Exclusive Luna Lagoon Badge
New environment for photos and mermaid-themed roleplay
This limited-time event allows players to trade mermaid-themed items, explore a stunning aquatic world, and unlock a rare necklace that lets you transform outfits instantly.
How to Access the Luna Lagoon Realm
You cannot teleport directly to Luna Lagoon from the standard world map. Instead, you must enter through the Mermaid Shop menu.
Steps to Teleport:
Open the Dress Up Menu.
Click on the Mermaid Shop.
Scroll until you see Mermaid Trading.
Select Mermaid Trading → click through the dialogue.
When prompted, choose “Let’s Go!”
You’ll be teleported to Luna Lagoon, complete with a short set of trading rules (just like the Trading Hub).
Once there, you’ll notice the realm’s glowing blue moonlight, waterfalls, seashells, and an underwater aesthetic — perfect for screenshots and roleplay.
The Mermaid Trading System
How to Trade
Luna Lagoon introduces a temporary trading feature where you can exchange mermaid items for a limited time during the event window.
Open your Diary.
Click on the Trading Button.
Select a player nearby and send a Trade Request.
Both players must click Accept to confirm.
Trading works exactly like in the Trading Hub, but this version is limited to mermaid-themed items and is only active during the Full Moon period (3 days each month).
Trade Example
The player traded an Aquamarine Princess Mermaid Potion for the Hibiscus Mermaid Tail Potion (Legendary).
The trading process awarded the Luna Lagoon Day 1 Badge, confirming participation in the event.
After completing your first trade, check your Diary → Badges section to see the Luna Lagoon badge unlocked.
The Secret Chest Location
A hidden chest in Luna Lagoon contains one of the most exciting items from this update — the Mermaid Transformation Necklace.
How to Find the Chest:
From the main spawn area, fly into the water near the glowing blue coral or seaweed patches.
Look for a small underwater cave illuminated by glowing plants.
Enter the cave and follow it to a hidden chamber.
Inside, you’ll find a glowing treasure chest.
Open it to trigger a beautiful animation sequence, after which you’ll receive the Mermaid Transformation Necklace.
The Mermaid Transformation Necklace Explained
Reward: Mermaid Transformation Necklace
Function: Lets you instantly change into any saved outfit when clicked in your inventory.
Type: Inventory transformation item (not an equippable accessory)
Appearance: A glowing aquamarine pendant resembling the magical items seen in Miraculous Ladybug.
How to Use It:
- Open your Inventory.
- Click on the Transformation Necklace.
- Instantly switch into any saved outfit of your choice.
This item is primarily for style changes and roleplay, not combat or gameplay bonuses, but it’s visually stunning and completely free to obtain.
Additional Realm Features
Luna Lagoon is designed as a scenic social hub with several aesthetic and interactive elements:
Underwater lighting and glowing corals
Waterfalls and crystal reflections
Diamond spawn points scattered around the area
Photo-ready spots — including laying down animations for posing
Mermaids and ambient creatures visible along the shore
It’s a small but highly detailed map — best suited for exploring, trading, and capturing screenshots.
Important Timers and Event Notes
Trading Period: Only available for 3 days during the Full Moon each month.
Full Moon Timer: Shown at the top of the screen (“Full Moon ends in 3 days and X hours”).
Mermaid Treasure Shop: Resets daily, but no confirmed new items were added in this update.
Badge: “Luna Lagoon Here from Day One” automatically unlocked upon your first trade.
Tip: Make all your trades early — once the Full Moon ends, trading will be disabled until the next cycle.
The Luna Lagoon update adds a refreshing, oceanic realm that blends trading, exploration, and style transformation into one experience.
While it’s primarily a social and trading event rather than a progression-heavy update, the Mermaid Transformation Necklace and the temporary trading system make it worth logging in for