Underwater

Underwater is a location just off the northern coast of Fossil Island. In order to enter the underwater area, a player must first travel to a small island via rowboat, located at the northern tip of the island (Transportation icon ). On this smaller island, a player can then select Dive on the rowboat to enter the underwater section. They will also find a bank on this island which can be used to quickly grab requires items.

While the Fishbowl helmet and Diving apparatus are not required to dive, it is heavily suggested that players bring them in order to extend their visit. Flippers can also by worn in order to swim faster. Weapons can be wielded underwater, however they prevent players from being able to swim. Attempting to access the deeper areas with a weapon equipped will cause the player to drown.

Air mechanics
When underwater, an oxygen meter will appear. This bar begins at 100% and reflects a player's supply of oxygen. As long as both the Fishbowl helmet and Diving apparatus are equipped, the bar will remain at 100%. If not, a player's oxygen will go down by 1% every few seconds. At 10% oxygen, the player's screen will begin flashing red, indicating that they will soon run out of air and drown. Drowning occurs when a player's oxygen levels drop to 0%. It doesn't cause any harm to the player, however it does come at a cost if the player has any mermaid tears in their inventory. Up to 15 tears will be taken by Mairin as payment for rescuing the player. Any tears in the player's bank will be left untouched.

To restore oxygen, players can either enter air bubbles which increase their oxygen by 5% every few seconds, or catch Pufferfish which can instantly restore oxygen by 15% and can be stored for later use.

Drift Net Fishing
This fishing activity requires at least 47 Fishing and 44 Hunter to begin. To be allowed access to the activity, players must first speak with Ceto, located just north of the anchor rope. 200 Numulite are required as payment to enter the instanced area and allowance lasts for a full day. Drift nets are tradeable and can be crafted by using 2 jute fibre on a loom at level 26 Crafting. These drift nets can then be strung up underwater to catch fish over time. Players with a Merfolk trident equipped will find it easier to capture fish shoals with the drift nets.

Upon harvesting a fully stocked net, the drift net will be destroyed leaving just the reward behind. Sardine, Tuna, Lobster, Swordfish, Shark, Oysters, and Pufferfish are all possible rewards from the net in varying amounts.

Seaweed Farming
Located just south of the anchor-rope, two seaweed patches can be used by players with at least 23 Farming. Seaweed spores are required for usage of the farming patch. A nearby mermaid, Mernia, requires 200 Numulite to watch over each patch.

Mermaid's Domain
The entire eastern area is an elaborate Agility and Thieving training arena. To enter, the player must first remove their Fishbowl helmet by the request of Mairin, a mermaid which guards the area. There is a pile of fishbowls which a player can use to store their helmet temporarily as they traverse the area. Without a helmet, players must rely on Pufferfish and air bubbles to keep their oxygen levels up.

After entering, players will find a scattered layout of treasure chests and giant clam shells as well as several tunnels, holes and other obstacles such as Currents which can be traversed. A flashing arrow on the player's screen and minimap indicates which chest or clam currently contains a reward. It should be noted that chests and clams can be looted multiple times after discovering the correct location.

There is a 1/8.5 chance that searching a chest or clam will be successful. On a successful search, a Mermaid's tear will always be rewarded, as well as a chance of receiving 20-30 Numulite or Unidentified fossils varying from small to rare. In addition to these items, a player is also awarded with both Agility and Thieving experience based on their current levels. At 70 Agility and 80 Thieving, a player can expect roughly 17k xp/hr for Agility and 80k xp/hr for Thieving.

Mermaid's tears are a form a currency which can be used only in Mairin's shop. Small, Medium, and Large Unidentified fossils, the Merfolk trident, and Seaweed spores can all be purchased here.

Combat
Level 68 lobstrosities can be found in the south-eastern area of the domain. These can only be attacked using a trident (Magic) or a brine sabre (melee). While players are not allowed to use their Fishbowl helmets here, there are several air bubbles which will help keep their oxygen levels up. Lobstrosities are favoured for their many seed and herb drops.

Personalities

 * Mairin - Runs Mairin's Market where players can buy an assortment of items.
 * Ceto - Allows access to a fishing and hunter activity.
 * Mernia - Looks after the Seaweed patch.

Music unlocked

 * Lagoon