On 25 February 1943, Sendai was reassigned to the Eighth Fleet at Rabaul under Vice Admiral Gunichi Mikawa and remained on patrol around Rabaul through April. Returning to Sasebo in May, Sendai was repaired and modified. Her No.5  gun mount was removed and two triple 25 mm AA gun mounts and Type 21 radar were installed.
On February 25, 1943, Sendai transferred from the Eighth Fleet at Rabaul under Vice Admiral Gunichi Mikawa to continue patrolling around Rabaul until April. In May, Sendai was repaired and modified in Sasebo. The No.5 gun mount was removed, and two triple 25 mm AA gun mounts and Type 21 radar were installed.