Negishi Line
In November 2000, two sets (66 and 67) were transferred to the Keihin–Tōhoku—Negishi Line and renumbered 80 and 81. In December 2003, the Chūō–Sōbu Line sets were reallocated to Mitaka Depot and renumbered 501–515. Between 2005 and 2006, set 515 was lent to the Keihin–Tōhoku—Negishi Line as a spare during car maintenance. Between 2006 and 2007, three more sets (513–515) were transferred to the Keihin–Tōhoku—Negishi Line to replace the prototype 209-900/910/920 series trains and renumbered 82–84. From October 2008, following the introduction of E233-1000 series trains on the Keihin–Tōhoku—Negishi Line, one set (80) was transferred back to the Chūō–Sōbu Line (as set 516) while the other four sets (81–84) were modified (with ATS-P/SN instead of ATC) and transferred to the Keiyō Line (as sets 31–34).