11 days after the Japanese attack, Philadelphia steamed for exercises in Casco Bay, after which she joined two destroyers for anti-submarine patrol to NS Argentia, Newfoundland. Returning to New York on 14 February 1942, she made two escort runs to Hafnarfjörður, Iceland. She then joined units of Task Force 22 (TF 22) at Norfolk on 16 May, departing two days later for an anti-submarine warfare sweep to the Panama Canal.
