|Release date||7 February 2006 (Update)|
|No. of banks||1|
|No. of altars||0|
|No. of obelisks||0|
|Teleportation||Mos Le Harmless 'rum', Pirate spell sheet|
|Music||In the Brine|
|Location on World Map|
Mos Le'Harmless is the quaint pirate base that players may visit after completion of Cabin Fever quest. The isle has a few attractions, such as the Trouble Brewing minigame and the Mos Le'Harmless Caves, where cave horrors may be found. It is the easternmost point of the RuneScape world map.
Mos Le'Harmless is initially traveled to by talking to Bill Teach aboard the eastern most boat at Port Phasmatys docks. Alternatively, a charter ship may be used from any port with trader crew members. This may only be attempted after starting the "Cabin Fever" quest. Bill Teach will not appear on the docks of Port Phasmatys until the quest is started and the option to travel to Mos Le'Harmless from charter ships will not be available.
You may also teleport there using the fairy ring code D•I•P, after completing Fairy Tale III - Orks Rift (see below). You need to repair the bridges with 8 planks (plain planks, not oak, teak, mahogany, nor protean planks), 16 nails and a hammer for the first time or else you can't get on the island. One bridge must be repaired while standing on the island, the other bridge MUST be repaired when standing on the isle.
- Trouble Brewing - A competitive minigame in which two teams brew 'rum'.
- Mos Le'Harmless Caves - These caves are full of cave horror, which are a Slayer target. A light source is required.
- Dodgy Mike's Second-hand Clothing - Sells pirate boots, pirate bandanas, stripy pirate shirts and pirate leggings.
- The jungle outside the gates- Contains jungle horrors and snakes that are stronger than the common poisonous variety and that always drop a snake hide.
- Charter Ship - Transports the player to various docks and ports around Runescape for a fee.
- Patchy - Sews together various items of clothing, such as a pirate hat and an eyepatch, for a fee of 500gp. (Eyepatches are not sold in the clothes shop, but they can be bought from the charter ship's general store.)
- Smith - In addition to his scimitar shop, he sells lucky cutlasses, Harry's cutlasses, and rapiers, as well as repairing the barrelchest anchor if you need a new one.
- Small obelisk - Used for recharging Summoning points. Found at the entrance to the cave.
- There are two small islands just to the north-east of the main island, accessible from the Mos Le'Harmless Caves. There is seaweed, edible seaweed, a teak tree and a Mahogany tree. (that goes for both of the small islands)
- Two Feet Charley owns a fish shop that sells a variety of fish such as lobsters and swordfish.
- Mos Le'Harmless has two bars where one can buy beer, braindeath 'rum', and stew.
- West of the entrance to the Mos Le'Harmless Caves there is a black slab with a carving of a black mask on it. If anything besides a chisel is used on the slab the player receives the message "Something sinister happens a long way off. But, for all intents and purposes, nothing interesting happens." A chisel can be used on the slab to get rock fragments, which can be used to feed an ex-ex-parrot.
- During Fairytale III - Orks Rift, a player will gain access to K'Chunk's island just south of Mos Le'Harmless' south coast, but the bridges to the main island are broken. After the quest, the player can repair the bridges. This requires 8 regular planks, 16 nails of any type, and a hammer. Use fairy ring D•I•P to go to the islands, go to the first bridge, and use a plank on the broken part of the bridge. It is repaired, using four planks and eight nails. The other bridge must be repaired from the Mos Le'Harmless side. Go to Mos Le'Harmless, go to the second bridge and then use a plank on the broken part of the bridge. The second bridge will be repaired, using up four planks and eight nails. Fairy ring D•I•P and the bridges are convenient access to the town on Mos Le'Harmless, and they are also convenient to get to the Mos Le'Harmless Caves and somewhat useful to get to Trouble Brewing.
In the Mos Le'Harmless Caves:
- Albino bat (level 43)
- Cave horror (level 77) (level 58 Slayer monster, witchwood icon needed to fight)
- Bill Teach
- Cavey Davey
- Honest Jimmy
- San Fan
- Fancy Dan
- Harpoon Joe
- Two Feet Charley
- Dodgy Mike
- Toothless Kevin
- Brother Tranquility
- 50 Ships Mufassah
- Brass Hand Harry
- Bard Roberts
- The name "Mos Le'Harmless" alludes to the The Hitchhiker's Guide to the Galaxy series by Douglas Adams, in which the Hitchhiker's Guide's entry on Earth is simply "Mostly Harmless".
- Mos Le'Harmless is featured as an Arcanists arena.
- The patch notes update on 4 August 2010 completely nerfed the rarity of high level impling spawns on Mos Le'Harmless. Previously, the island was a popular place for impling hunters because of the respawn points that commonly produced implings ranging from nature to kingly.
- The only accessible part of Mos Le'Harmless used to be the town, which was surrounded in Unknown, but after an update the entire sea around it, the jungle, Harmony Island and the Trouble Brewing minigame became accessible.