O2 (United Kingdom)
（重定向自Cellnet）
![](/Images/godic/202501/03/O2_logo.svg4949.png"){kind=logo}
![The O2 offices in Leeds](/Images/godic/202501/03/O2_Offices_in_Leeds4950.jpg")
![The O2 entrance](/Images/godic/202501/03/The_O2_Arena,_entrance4950.jpg")
![](/Images/godic/202501/03/BT_Tower-14950.jpg")
Telefónica UK Limited (trading as O2 – stylised as O2) is a telecommunications services provider in the United Kingdom owned by the Spanish multinational Telefónica. It is the second-largest mobile telecommunications provider in the United Kingdom after EE Limited, and is headquartered in Slough.