the 15th escort squadron was deactivated on 10 april 1942 and "isuzu" was reassigned to rear admiral kenzaburo hara's crudiv 16 under vice admiral ibō takahashi's 2nd southern expeditionary fleet. she was joined by the and and was assigned a patrol area in the dutch east indies extending from makassar, celebes to balikpapan, borneo and surabaya, java, becoming flagship of crudiv 16 from 1 may 1942.