A list of the most noteworthy RuneScape updates and events in 2005:
- 5 January - Troll Romance is released.
- 10 January - In Search of the Myreque is added.
- 26 January - Slayer was released.
- Creature of Fenkenstrain quest is added.
- Jagex began updating graphics in the free world.
- 7 February - Roving Elves is added.
- 15 February - Ghosts Ahoy quest is added.
- 28 February - One Small Favour quest is added.
- 7 March - Mountain Daughter quest is added
- 21 March - The 2005 Easter event occurred for about two weeks. Rubber chickens were given as a reward. Between a Rock... quest is added
- 4 April - Behind the Scenes - April, The Feud quest is added
- 8 April - The RuneScape Wiki is created.
- 11 April - The Golem quest is added.
- 18 April - Desert Treasure and its reward, the Ancient Magicks spellbook, were released.
- 26 April - Icthlarin's Little Helper is added
- 4 May - Behind the Scenes - May. Tears of Guthix quest is released.
- 9 May - Game update: Barrows
- 17 May - Zogre Flesh Eaters is added.
- 31 May - Keldagrim was released along with the quest The Giant Dwarf. The Lost Tribe is added.
- 6 June - Behind the Scenes - June
- 6 June - Seeds and farming tools were released.
- 13 June - Tiaras, combination runes, and the Abyss were released.
- 27 June - Recruitment Drive is added.
- 5 July - Behind the Scenes - July
- 9 July - First player reaches maximum skill total.
- 11 July - Farming skill released.
- 19 July - Mourning's Ends Part I is added.
- 26 July - Forgettable Tale... quest is added.
- 8 August - Behind the Scenes - August
- 22 August - Return of the Letters page
- 25 August - The Hiscores were changed to show the top 500,000 players in each skill, versus the top 100,000.
- 30 August - Garden of Tranquility quest is added.
- 5 September - Behind the Scenes - September
- 12 September - Cook-X was added.
- 19 September - Bank PINs were introduced.
- 26 September - New readers letters becomes the first issue of Postbag from the Hedge
- 26 September - The Mouse toy was released along with the quest A Tail of Two Cats.
- 4 October - Behind the Scenes - October
- 4 October - TzHaar Fight Cave was added.
- 17 October - Mourning's Ends Part II was released. Wanted! quest is added
- 31 October - 2005 Hallowe'en event, (31 October through 7 November). Rum Deal is added.
- 3 November - Behind the Scenes - November
- 7 November - Dagannoth Prime
- 14 November - Shadow of the Storm is added.
- 22 November - Making History is added.
- 28 November - Ratcatchers is added.
- 5 December - Behind the Scenes - December, Tool leprechauns were added to the game, Spirits of the Elid was released, along with Nardah
- 12 December - Champions' Challenge is released, Skeletal Wyverns were added to the game
- 19 December - 2005 Christmas event, (19 December through 4 January 2006); Devious Minds was released