| February | |
| 04 | The special program "'Music Station' Looks Back on 20 Years of L'Arc～en～Ciel" is broadcast on TV Asahi in honor of L'Arc～en～Ciel's 20th anniversary |
| 05 | L'Arc～en～Ciel appears on Nippon Television Network's program "Music Lovers" |
| 06-10 | L'Arc～en～Ciel appears on TV Asahi's program "Ontama" |
| 08 | "BUTTERFLY" is released and debuts at No. 1 on the Oricon chart |
| 10 | L'Arc～en～Ciel appears on TV Asahi's program "MUSIC STATION" |
| 11 | L'Arc～en～Ciel appears on NHK General's "L'Arc～en～Ciel's 20-Year Journey" program |
| 22-23 | L'Arc～en～Ciel's "LE-CIEL Members Only Concert" is held at Yokohama Arena |
| March | |
| 03 | L'Arc～en～Ciel's WORLD TOUR 2012 begins! The band preforms in front of 450,000 people in a 17-concert tour across 14 cities in 10 countries. L'Arc～en～Ciel performs in Hong Kong at the Asia World EXPO ARENA as part of WORLD TOUR 2012 The band begins selling their best-of album "WORLD'S BEST SELECTION" to only those attending the overseas performances |
| 07 | L'Arc～en～Ciel performs in Bangkok at IMPACT ARENA as part of WORLD TOUR 2012 The official sheet music for "BUTTERFLY" is released |
| 10 | L'Arc～en～Ciel performs in Shanghai at MERCEDES-BENZ ARENA as part of WORLD TOUR 2012 |
| 17 | L'Arc～en～Ciel performs in Taipei at WTC Nangang Exhibition Hall as part of WORLD TOUR 2012 |
| 25 | L'Arc～en～Ciel performs in New York City at Madison Square Garden as part of WORLD TOUR 2012 In a first among Japanese artists, the entire concert is broadcast live to movie theaters throughout Japan (with delay in some locations) |
| April | |
| 11 | L'Arc～en～Ciel performs in London at indigO2 as part of WORLD TOUR 2012 |
| 14 | L'Arc～en～Ciel performs in Paris at Le Zenith as part of WORLD TOUR 2012 |
| 20 | A L'Arc～en～Ciel "Premium Night," one-night-only performance is held at Liquidroom in Ebisu 100,000 fans are selected in a lottery to view a live broadcast of the performance via USTREAM |
| 28 | L'Arc～en～Ciel performs in Singapore at Singapore Indoor Stadium as part of WORLD TOUR 2012 |
| May | |
| 02 | L'Arc～en～Ciel performs in Jakarta at Lapangan D Senayan as part of WORLD TOUR 2012 |
| 05 | L'Arc～en～Ciel performs in Seoul at Jamsil Gymnasium as part of WORLD TOUR 2012 |
| 12-13 | L'Arc～en～Ciel performs in Yokohama at Nissan Stadium as part of 20th L'Anniversary WORLD TOUR 2012 THE FINAL |
| 19-20 | L'Arc～en～Ciel performs in Osaka at Universal Studios Japan on a special outdoor stage as part of 20th L'Anniversary WORLD TOUR 2012 THE FINAL |
| 23 | The English version of "XXX" is released as a digital download The English version of "Chase" is released as a digital download |
| 26-27 | L'Arc～en～Ciel performs in Tokyo at National Olympic Stadium as part of 20th L'Anniversary WORLD TOUR 2012 THE FINAL |
| 31 | L'Arc～en～Ciel performs in Hawaii at Waikiki Shell as part of WORLD TOUR 2012 The city of Honolulu establishes "L'Arc～en～Ciel Day" |
| June | |
| 01 | The special concert "LE-CIEL Presents Hawaii en Ciel" is held in Hawaii at Waikiki Shell |
| 04-10 | "L'Arc～en～Ciel PREMIRE SCREENING Supported by Sony and Ki/oon Music" is held |
| 09 | "L'Arc～en～Ciel 20th L'Anniversary EXHIBITION" open at Yokosuka Museum of Art and runs through July 8 |
| 13 | The live DVD「LIVE TWENITY」is released and debuts at No. 2 on the Oricon chart |
| July | |
| 28 | "LE-CIEL Extra Number" is released |
| October | |
| 31 | "LIFE 2" and "LIVE 2" are released |
| November | |
| 07 | L'Arc～en～Ciel's music becomes available for download via the iTunes Store |
| December | |
| 21 | L'Arc～en～Ciel appears on TV Asahi's program "MUSIC STATION SUPER LIVE 2012" |
| 26 | The live DVD "WORLD TOUR 2012 LIVE at MADISON SQUARE GARDEN" is released and debuts at No. 2 on the Oricon chart |
